Functionalized polymers

ABSTRACT

A method for preparing a functionalized polymer, the method comprising the steps of: (i) polymerizing monomer to form a reactive polymer, and (ii) reacting the reactive polymer with an azodiester.

This application claims the benefit of U.S. Provisional Application Ser.No. 61/748,266, filed on Jan. 2, 2013, which is incorporated herein byreference.

FIELD OF THE INVENTION

One or more embodiments of the present invention relate to polymersfunctionalized with azodiesters.

BACKGROUND OF THE INVENTION

In the art of manufacturing tires, it is desirable to employ rubbervulcanizates that demonstrate reduced hysteresis, i.e., less loss ofmechanical energy to heat. For example, rubber vulcanizates that showreduced hysteresis are advantageously employed in tire components, suchas sidewalls and treads, to yield tires having desirably low rollingresistance. The hysteresis of a rubber vulcanizate is often attributedto the free polymer chain ends within a crosslinked rubber network, aswell as the dissociation of filler agglomerates.

Functionalized polymers have been employed to reduce the hysteresis ofrubber vulcanizates. The functional group of the functionalized polymermay reduce the number of free polymer chain ends via interaction withfiller particles. Also, the functional group may reduce filleragglomeration. Nevertheless, whether a particular functional groupimparted to a polymer can reduce hysteresis is often unpredictable.

Functionalized polymers may be prepared by post-polymerization treatmentof reactive polymers with certain functionalizing agents. However,whether a reactive polymer can be functionalized by treatment with aparticular functionalizing agent can be unpredictable. For example,functionalizing agents that work for one type of polymer do notnecessarily work for another type of polymer, and vice versa.

Lanthanide-based catalyst systems are known to be useful forpolymerizing conjugated diene monomer to form polydienes having a highcontent of cis-1,4-linkage. The resulting cis-1,4-polydienes may displaypseudo-living characteristics in that, upon completion of thepolymerization, some of the polymer chains possess reactive ends thatcan react with certain functionalizing agents to yield functionalizedcis-1,4-polydienes.

The cis-1,4-polydienes produced with lanthanide-based catalyst systemstypically have a linear backbone, which is believed to provide bettertensile properties, higher abrasion resistance, lower hysteresis, andbetter fatigue resistance as compared to the cis-1,4-polydienes preparedwith other catalyst systems such as titanium-, cobalt-, and nickel-basedcatalyst systems. Therefore, the cis-1,4-polydienes made withlanthanide-based catalysts are particularly suitable for use in tirecomponents such as sidewalls and treads. However, one disadvantage ofthe cis-1,4-polydienes prepared with lanthanide-based catalysts is thatthe polymers exhibit high cold flow due to their linear backbonestructure. The high cold flow causes problems during storage andtransport of the polymers and also hinders the use of automatic feedingequipment in rubber compound mixing facilities.

Anionic initiators are known to be useful for the polymerization ofconjugated diene monomer to form polydienes having a combination of1,2-, cis-1,4- and trans-1,4-linkages. Anionic initiators are alsouseful for the copolymerization of conjugated diene monomer withvinyl-substituted aromatic compounds. The polymers prepared with anionicinitiators may display living characteristics in that, upon completionof the polymerization, the polymer chains possess living ends that arecapable of reacting with additional monomer for further chain growth orreacting with certain functionalizing agents to give functionalizedpolymers. Without the introduction of any coupled or branchedstructures, the polymers prepared with anionic initiators may alsoexhibit the problem of high cold flow.

Because functionalized polymers are advantageous, especially in themanufacture of tires, there exists a need to develop new functionalizedpolymers that give reduced hysteresis and reduced cold flow.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provide a method forpreparing a functionalized polymer, the method comprising the steps of:(i) polymerizing monomer to form a reactive polymer, and (ii) reactingthe reactive polymer with an azodiester.

One or more embodiments of the present invention further provide amethod for preparing a functionalized polymer, the method comprising thesteps of: (i) polymerizing conjugated diene monomer, and optionallymonomer copolymerizable therewith, to form a polymer having a reactivechain end; and (ii) reacting the reactive chain end of the polymer withan azodiester.

One or more embodiments of the present invention further provide afunctionalized polymer prepared by the steps of: (i) polymerizingconjugated diene monomer, and optionally monomer copolymerizabletherewith, to form a polymer having a reactive chain end; and (ii)reacting the reactive chain end of the polymer with an azodiester.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical plot of cold-flow gauge (mm at 8 min) versusMooney viscosity (ML₁₊₄ at 100° C.) for functionalizedcis-1,4-polybutadiene prepared according to one or more embodiments ofthe present invention as compared to unfunctionalizedcis-1,4-polybutadiene.

FIG. 2 is a graphical plot of hysteresis loss (tan δ) versus Mooneyviscosity (ML₁₊₄ at 130° C.) for vulcanizates prepared fromfunctionalized cis-1,4-polybutadiene prepared according to one or moreembodiments of the present invention as compared to vulcanizatesprepared from unfunctionalized cis-1,4-polybutadiene.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

According to one or more embodiments of the present invention, areactive polymer is prepared by polymerizing conjugated diene monomerand optionally monomer copolymerizable therewith, and this reactivepolymer is then functionalized by reaction with an azodiester. Theresultant functionalized polymers can be used in the manufacture of tirecomponents. In one or more embodiments, the resultant functionalizedpolymers exhibit advantageous cold-flow resistance and provide tirecomponents that exhibit advantageously low hysteresis.

Examples of conjugated diene monomer include 1,3-butadiene, isoprene,1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene,2-ethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene,4-methyl-1,3-pentadiene, and 2,4-hexadiene. Mixtures of two or moreconjugated dienes may also be utilized in copolymerization.

Examples of monomer copolymerizable with conjugated diene monomerinclude vinyl-substituted aromatic compounds such as styrene,p-methylstyrene, α-methylstyrene, and vinylnaphthalene.

In one or more embodiments, the reactive polymer is prepared bycoordination polymerization, wherein monomer is polymerized by using acoordination catalyst system. The key mechanistic features ofcoordination polymerization have been discussed in books (e.g., Kuran,W., Principles of Coordination Polymerization; John Wiley & Sons: NewYork, 2001) and review articles (e.g., Mulhaupt, R., MacromolecularChemistry and Physics 2003, volume 204, pages 289-327). Coordinationcatalysts are believed to initiate the polymerization of monomer by amechanism that involves the coordination or complexation of monomer toan active metal center prior to the insertion of monomer into a growingpolymer chain. An advantageous feature of coordination catalysts istheir ability to provide stereochemical control of polymerizations andthereby produce stereoregular polymers. As is known in the art, thereare numerous methods for creating coordination catalysts, but allmethods eventually generate an active intermediate that is capable ofcoordinating with monomer and inserting monomer into a covalent bondbetween an active metal center and a growing polymer chain. Thecoordination polymerization of conjugated dienes is believed to proceedvia x-allyl complexes as intermediates. Coordination catalysts can beone-, two-, three- or multi-component systems. In one or moreembodiments, a coordination catalyst may be formed by combining a heavymetal compound (e.g., a transition metal compound or alanthanide-containing compound), an alkylating agent (e.g., anorganoaluminum compound), and optionally other co-catalyst components(e.g., a Lewis acid or a Lewis base). In one or more embodiments, theheavy metal compound may be referred to as a coordinating metalcompound.

Various procedures can be used to prepare coordination catalysts. In oneor more embodiments, a coordination catalyst may be formed in situ byseparately adding the catalyst components to the monomer to bepolymerized in either a stepwise or simultaneous manner. In otherembodiments, a coordination catalyst may be preformed. That is, thecatalyst components are pre-mixed outside the polymerization systemeither in the absence of any monomer or in the presence of a smallamount of monomer. The resulting preformed catalyst composition may beaged, if desired, and then added to the monomer that is to bepolymerized.

Useful coordination catalyst systems include lanthanide-based catalystsystems. These catalyst systems may advantageously producecis-1,4-polydienes that, prior to quenching, have reactive chain endsand may be referred to as pseudo-living polymers. While othercoordination catalyst systems may also be employed, lanthanide-basedcatalysts have been found to be particularly advantageous, andtherefore, without limiting the scope of the present invention, will bediscussed in greater detail.

Practice of the present invention is not necessarily limited by theselection of any particular lanthanide-based catalyst system. In one ormore embodiments, the catalyst systems employed include (a) alanthanide-containing compound, (b) an alkylating agent, and (c) ahalogen source. In other embodiments, a compound containing anon-coordinating anion or a non-coordinating anion precursor can beemployed in lieu of a halogen source. In these or other embodiments,other organometallic compounds, Lewis bases, and/or catalyst modifierscan be employed in addition to the ingredients or components set forthabove. For example, in one embodiment, a nickel-containing compound canbe employed as a molecular weight regulator as disclosed in U.S. Pat.No. 6,699,813, which is incorporated herein by reference.

As mentioned above, the lanthanide-based catalyst systems employed inthe present invention can include a lanthanide-containing compound.Lanthanide-containing compounds useful in the present invention arethose compounds that include at least one atom of lanthanum, neodymium,cerium, praseodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, anddidymium. In one embodiment, these compounds can include neodymium,lanthanum, samarium, or didymium. As used herein, the term “didymium”shall denote a commercial mixture of rare-earth elements obtained frommonazite sand. In addition, the lanthanide-containing compounds usefulin the present invention can be in the form of elemental lanthanide.

The lanthanide atom in the lanthanide-containing compounds can be invarious oxidation states including, but not limited to, the 0, +2, +3,and +4 oxidation states. In one embodiment, a trivalentlanthanide-containing compound, where the lanthanide atom is in the +3oxidation state, can be employed. Suitable lanthanide-containingcompounds include, but are not limited to, lanthanide carboxylates,lanthanide organophosphates, lanthanide organophosphonates, lanthanideorganophosphinates, lanthanide carbamates, lanthanide dithiocarbamates,lanthanide xanthates, lanthanide β-diketonates, lanthanide alkoxides oraryloxides, lanthanide halides, lanthanide pseudo-halides, lanthanideoxyhalides, and organolanthanide compounds.

In one or more embodiments, the lanthanide-containing compounds can besoluble in hydrocarbon solvents such as aromatic hydrocarbons, aliphatichydrocarbons, or cycloaliphatic hydrocarbons. Hydrocarbon-insolublelanthanide-containing compounds, however, may also be useful in thepresent invention, as they can be suspended in the polymerization mediumto form the catalytically active species.

For ease of illustration, further discussion of usefullanthanide-containing compounds will focus on neodymium compounds,although those skilled in the art will be able to select similarcompounds that are based upon other lanthanide metals.

Suitable neodymium carboxylates include, but are not limited to,neodymium formate, neodymium acetate, neodymium acrylate, neodymiummethacrylate, neodymium valerate, neodymium gluconate, neodymiumcitrate, neodymium fumarate, neodymium lactate, neodymium maleate,neodymium oxalate, neodymium 2-ethylhexanoate, neodymium neodecanoate(a.k.a., neodymium versatate), neodymium naphthenate, neodymiumstearate, neodymium oleate, neodymium benzoate, and neodymiumpicolinate.

Suitable neodymium organophosphates include, but are not limited to,neodymium dibutyl phosphate, neodymium dipentyl phosphate, neodymiumdihexyl phosphate, neodymium diheptyl phosphate, neodymium dioctylphosphate, neodymium bis(1-methylheptyl)phosphate, neodymiumbis(2-ethylhexyl)phosphate, neodymium didecyl phosphate, neodymiumdidodecyl phosphate, neodymium dioctadecyl phosphate, neodymium dioleylphosphate, neodymium diphenyl phosphate, neodymiumbis(p-nonylphenyl)phosphate, neodymium butyl (2-ethylhexyl)phosphate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphate, andneodymium(2-ethylhexyl)(p-nonylphenyl)phosphate.

Suitable neodymium organophosphonates include, but are not limited to,neodymium butyl phosphonate, neodymium pentyl phosphonate, neodymiumhexyl phosphonate, neodymium heptyl phosphonate, neodymium octylphosphonate, neodymium(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)phosphonate, neodymium decyl phosphonate,neodymium dodecyl phosphonate, neodymium octadecyl phosphonate,neodymium oleyl phosphonate, neodymium phenyl phosphonate,neodymium(p-nonylphenyl)phosphonate, neodymium butyl butylphosphonate,neodymium pentyl pentylphosphonate, neodymium hexyl hexylphosphonate,neodymium heptyl heptylphosphonate, neodymium octyl octylphosphonate,neodymium(1-methylheptyl)(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)(2-ethylhexyl)phosphonate, neodymium decyldecylphosphonate, neodymium dodecyl dodecylphosphonate, neodymiumoctadecyl octadecylphosphonate, neodymium oleyl oleylphosphonate,neodymium phenyl phenylphosphonate,neodymium(p-nonylphenyl)(p-nonylphenyl)phosphonate, neodymium butyl(2-ethylhexyl)phosphonate, neodymium(2-ethylhexyl)butylphosphonate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphonate,neodymium(2-ethylhexyl)(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)(p-nonylphenyl)phosphonate, andneodymium(p-nonylphenyl)(2-ethylhexyl)phosphonate.

Suitable neodymium organophosphinates include, but are not limited to,neodymium butylphosphinate, neodymium pentylphosphinate, neodymiumhexylphosphinate, neodymium heptylphosphinate, neodymiumoctylphosphinate, neodymium(1-methylheptyl)phosphinate,neodymium(2-ethylhexyl)phosphinate, neodymium decylphosphinate,neodymium dodecylphosphinate, neodymium octadecylphosphinate, neodymiumoleylphosphinate, neodymium phenylphosphinate,neodymium(p-nonylphenyl)phosphinate, neodymium dibutylphosphinate,neodymium dipentylphosphinate, neodymium dihexylphosphinate, neodymiumdiheptylphosphinate, neodymium dioctylphosphinate, neodymiumbis(1-methylheptyl)phosphinate, neodymium bis(2-ethylhexyl)phosphinate,neodymium didecylphosphinate, neodymium didodecylphosphinate, neodymiumdioctadecylphosphinate, neodymium dioleylphosphinate, neodymiumdiphenylphosphinate, neodymium bis(p-nonylphenyl)phosphinate, neodymiumbutyl (2-ethylhexyl)phosphinate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphinate, andneodymium(2-ethylhexyl)(p-nonylphenyl)phosphinate.

Suitable neodymium carbamates include, but are not limited to, neodymiumdimethylcarbamate, neodymium diethylcarbamate, neodymiumdiisopropylcarbamate, neodymium dibutylcarbamate, and neodymiumdibenzylcarbamate.

Suitable neodymium dithiocarbamates include, but are not limited to,neodymium dimethyldithiocarbamate, neodymium diethyldithiocarbamate,neodymium diisopropyldithiocarbamate, neodymium dibutyldithiocarbamate,and neodymium dibenzyldithiocarbamate.

Suitable neodymium xanthates include, but are not limited to, neodymiummethylxanthate, neodymium ethylxanthate, neodymium isopropylxanthate,neodymium butylxanthate, and neodymium benzylxanthate.

Suitable neodymium β-diketonates include, but are not limited to,neodymium acetylacetonate, neodymium trifluoroacetylacetonate, neodymiumhexafluoroacetylacetonate, neodymium benzoylacetonate, and neodymium2,2,6,6-tetramethyl-3,5-heptanedionate.

Suitable neodymium alkoxides or aryloxides include, but are not limitedto, neodymium methoxide, neodymium ethoxide, neodymium isopropoxide,neodymium 2-ethylhexoxide, neodymium phenoxide, neodymiumnonylphenoxide, and neodymium naphthoxide.

Suitable neodymium halides include, but are not limited to, neodymiumfluoride, neodymium chloride, neodymium bromide, and neodymium iodide.Suitable neodymium pseudo-halides include, but are not limited to,neodymium cyanide, neodymium cyanate, neodymium thiocyanate, neodymiumazide, and neodymium ferrocyanide. Suitable neodymium oxyhalidesinclude, but are not limited to, neodymium oxyfluoride, neodymiumoxychloride, and neodymium oxybromide. A Lewis base, such astetrahydrofuran (“THF”), may be employed as an aid for solubilizing thisclass of neodymium compounds in inert organic solvents. Where lanthanidehalides, lanthanide oxyhalides, or other lanthanide-containing compoundscontaining a halogen atom are employed, the lanthanide-containingcompound may optionally also provide all or part of the halogen sourcein the lanthanide-based catalyst system.

As used herein, the term organolanthanide compound refers to anylanthanide-containing compound containing at least one lanthanide-carbonbond. These compounds are predominantly, though not exclusively, thosecontaining cyclopentadienyl (“Cp”), substituted cyclopentadienyl, allyl,and substituted allyl ligands. Suitable organolanthanide compoundsinclude, but are not limited to, Cp₃Ln, Cp₂LnR, Cp₂LnCl, CpLnCl₂,CpLn(cyclooctatetraene), (C₅Me₅)₂LnR, LnR₃, Ln(allyl)₃, andLn(allyl)₂Cl, where Ln represents a lanthanide atom, and R represents ahydrocarbyl group. In one or more embodiments, hydrocarbyl groups usefulin the present invention may contain heteroatoms such as, for example,nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms.

As mentioned above, the lanthanide-based catalyst systems employed inthe present invention can include an alkylating agent. In one or moreembodiments, alkylating agents, which may also be referred to ashydrocarbylating agents, include organometallic compounds that cantransfer one or more hydrocarbyl groups to another metal. Generally,these agents include organometallic compounds of electropositive metalssuch as Groups 1, 2, and 3 metals (Groups IA, IIA, and IIIA metals).Alkylating agents useful in the present invention include, but are notlimited to, organoaluminum and organomagnesium compounds. As usedherein, the term organoaluminum compound refers to any aluminum compoundcontaining at least one aluminum-carbon bond. In one or moreembodiments, organoaluminum compounds that are soluble in a hydrocarbonsolvent can be employed. As used herein, the term organomagnesiumcompound refers to any magnesium compound that contains at least onemagnesium-carbon bond. In one or more embodiments, organomagnesiumcompounds that are soluble in a hydrocarbon can be employed. As will bedescribed in more detail below, several species of suitable alkylatingagents can be in the form of a halide. Where the alkylating agentincludes a halogen atom, the alkylating agent may also serve as all orpart of the halogen source in the above-mentioned catalyst system.

In one or more embodiments, organoaluminum compounds that can beutilized in the lanthanide-based catalyst system include thoserepresented by the general formula AlR_(n)X_(3−n), where each Rindependently can be a monovalent organic group that is attached to thealuminum atom via a carbon atom, where each X independently can be ahydrogen atom, a halogen atom, a carboxylate group, an alkoxide group,or an aryloxide group, and where n can be an integer in the range offrom 1 to 3. In one or more embodiments, each R independently can be ahydrocarbyl group such as, for example, alkyl, cycloalkyl, substitutedcycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, aryl,substituted aryl, aralkyl, alkaryl, allyl, and alkynyl groups, with eachgroup containing in the range of from 1 carbon atom, or the appropriateminimum number of carbon atoms to form the group, up to about 20 carbonatoms. These hydrocarbyl groups may contain heteroatoms including, butnot limited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorusatoms.

Types of the organoaluminum compounds that are represented by thegeneral formula AlR_(n)X_(3−n) include, but are not limited to,trihydrocarbylaluminum, dihydrocarbylaluminum hydride,hydrocarbylaluminum dihydride, dihydrocarbylaluminum carboxylate,hydrocarbylaluminum bis(carboxylate), dihydrocarbylaluminum alkoxide,hydrocarbylaluminum dialkoxide, dihydrocarbylaluminum halide,hydrocarbylaluminum dihalide, dihydrocarbylaluminum aryloxide, andhydrocarbylaluminum diaryloxide compounds. In one embodiment, thealkylating agent can comprise trihydrocarbylaluminum,dihydrocarbylaluminum hydride, and/or hydrocarbylaluminum dihydridecompounds. In one embodiment, when the alkylating agent includes anorganoaluminum hydride compound, the above-mentioned halogen source canbe provided by a tin halide, as disclosed in U.S. Pat. No. 7,008,899,which is incorporated herein by reference in its entirety.

Suitable trihydrocarbylaluminum compounds include, but are not limitedto, trimethylaluminum, triethylaluminum, triisobutylaluminum,tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum,tri-t-butylaluminum, tri-n-pentylaluminum, trineopentylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, tris(2-ethylhexyl)aluminum,tricyclohexylaluminum, tris(1-methylcyclopentyl)aluminum,triphenylaluminum, tri-p-tolylaluminum,tris(2,6-dimethylphenyl)aluminum, tribenzylaluminum,diethylphenylaluminum, diethyl-p-tolylaluminum, diethylbenzylaluminum,ethyldiphenylaluminum, ethyldi-p-tolylaluminum, andethyldibenzylaluminum.

Suitable dihydrocarbylaluminum hydride compounds include, but are notlimited to, diethylaluminum hydride, di-n-propylaluminum hydride,diisopropylaluminum hydride, di-n-butylaluminum hydride,diisobutylaluminum hydride, di-n-octylaluminum hydride, diphenylaluminumhydride, di-p-tolylaluminum hydride, dibenzylaluminum hydride,phenylethylaluminum hydride, phenyl-n-propylaluminum hydride,phenylisopropylaluminum hydride, phenyl-n-butylaluminum hydride,phenylisobutylaluminum hydride, phenyl-n-octylaluminum hydride,p-tolylethylaluminum hydride, p-tolyl-n-propylaluminum hydride,p-tolylisopropylaluminum hydride, p-tolyl-n-butylaluminum hydride,p-tolylisobutylaluminum hydride, p-tolyl-n-octylaluminum hydride,benzylethylaluminum hydride, benzyl-n-propylaluminum hydride,benzylisopropylaluminum hydride, benzyl-n-butylaluminum hydride,benzylisobutylaluminum hydride, and benzyl-n-octylaluminum hydride.

Suitable hydrocarbylaluminum dihydrides include, but are not limited to,ethylaluminum dihydride, n-propylaluminum dihydride, isopropylaluminumdihydride, n-butylaluminum dihydride, isobutylaluminum dihydride, andn-octylaluminum dihydride.

Suitable dihydrocarbylaluminum halide compounds include, but are notlimited to, diethylaluminum chloride, di-n-propylaluminum chloride,diisopropylaluminum chloride, di-n-butylaluminum chloride,diisobutylaluminum chloride, di-n-octylaluminum chloride,diphenylaluminum chloride, di-p-tolylaluminum chloride, dibenzylaluminumchloride, phenylethylaluminum chloride, phenyl-n-propylaluminumchloride, phenylisopropylaluminum chloride, phenyl-n-butylaluminumchloride, phenylisobutylaluminum chloride, phenyl-n-octylaluminumchloride, p-tolylethylaluminum chloride, p-tolyl-n-propylaluminumchloride, p-tolylisopropylaluminum chloride, p-tolyl-n-butylaluminumchloride, p-tolylisobutylaluminum chloride, p-tolyl-n-octylaluminumchloride, benzylethylaluminum chloride, benzyl-n-propylaluminumchloride, benzylisopropylaluminum chloride, benzyl-n-butylaluminumchloride, benzylisobutylaluminum chloride, and benzyl-n-octylaluminumchloride.

Suitable hydrocarbylaluminum dihalide compounds include, but are notlimited to, ethylaluminum dichloride, n-propylaluminum dichloride,isopropylaluminum dichloride, n-butylaluminum dichloride,isobutylaluminum dichloride, and n-octylaluminum dichloride.

Other organoaluminum compounds useful as alkylating agents that may berepresented by the general formula AlR_(n)X_(3−n) include, but are notlimited to, dimethylaluminum hexanoate, diethylaluminum octoate,diisobutylaluminum 2-ethylhexanoate, dimethylaluminum neodecanoate,diethylaluminum stearate, diisobutylaluminum oleate, methylaluminumbis(hexanoate), ethylaluminum bis(octoate), isobutylaluminumbis(2-ethylhexanoate), methylaluminum bis(neodecanoate), ethylaluminumbis(stearate), isobutylaluminum bis(oleate), dimethylaluminum methoxide,diethylaluminum methoxide, diisobutylaluminum methoxide,dimethylaluminum ethoxide, diethylaluminum ethoxide, diisobutylaluminumethoxide, dimethylaluminum phenoxide, diethylaluminum phenoxide,diisobutylaluminum phenoxide, methylaluminum dimethoxide, ethylaluminumdimethoxide, isobutylaluminum dimethoxide, methylaluminum diethoxide,ethylaluminum diethoxide, isobutylaluminum diethoxide, methylaluminumdiphenoxide, ethylaluminum diphenoxide, and isobutylaluminumdiphenoxide.

Another class of organoaluminum compounds suitable for use as analkylating agent in the lanthanide-based catalyst system isaluminoxanes. Aluminoxanes can comprise oligomeric linear aluminoxanes,which can be represented by the general formula:

and oligomeric cyclic aluminoxanes, which can be represented by thegeneral formula:

where x can be an integer in the range of from 1 to about 100, or about10 to about 50; y can be an integer in the range of from 2 to about 100,or about 3 to about 20; and where each R independently can be amonovalent organic group that is attached to the aluminum atom via acarbon atom. In one embodiment, each R independently can be ahydrocarbyl group including, but not limited to, alkyl, cycloalkyl,substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl,aryl, substituted aryl, aralkyl, alkaryl, allyl, and alkynyl groups,with each group containing in the range of from 1 carbon atom, or theappropriate minimum number of carbon atoms to form the group, up toabout 20 carbon atoms. These hydrocarbyl groups may also containheteroatoms including, but not limited to, nitrogen, oxygen, boron,silicon, sulfur, and phosphorus atoms. It should be noted that thenumber of moles of the aluminoxane as used in this application refers tothe number of moles of the aluminum atoms rather than the number ofmoles of the oligomeric aluminoxane molecules. This convention iscommonly employed in the art of catalyst systems utilizing aluminoxanes.

Aluminoxanes can be prepared by reacting trihydrocarbylaluminumcompounds with water. This reaction can be performed according to knownmethods, such as, for example, (1) a method in which thetrihydrocarbylaluminum compound is dissolved in an organic solvent andthen contacted with water, (2) a method in which thetrihydrocarbylaluminum compound is reacted with water of crystallizationcontained in, for example, metal salts, or water adsorbed in inorganicor organic compounds, or (3) a method in which thetrihydrocarbylaluminum compound is reacted with water in the presence ofthe monomer or monomer solution that is to be polymerized.

Suitable aluminoxane compounds include, but are not limited to,methylaluminoxane (“MAO”), modified methylaluminoxane (“MMAO”),ethylaluminoxane, n-propylaluminoxane, isopropylaluminoxane,butylaluminoxane, isobutylaluminoxane, n-pentylaluminoxane,neopentylaluminoxane, n-hexylaluminoxane, n-octylaluminoxane,2-ethylhexylaluminoxane, cyclohexylaluminoxane,1-methylcyclopentylaluminoxane, phenylaluminoxane, and2,6-dimethylphenylaluminoxane. Modified methylaluminoxane can be formedby substituting about 20 to 80 percent of the methyl groups ofmethylaluminoxane with C₂ to C₁₂ hydrocarbyl groups, preferably withisobutyl groups, by using techniques known to those skilled in the art.

In one or more embodiments, aluminoxanes can be used alone or incombination with other organoaluminum compounds. In one embodiment,methylaluminoxane and at least one other organoaluminum compound (e.g.,AlR_(n)X_(3−n)), such as diisobutyl aluminum hydride, can be employed incombination. U.S. Publication No. 2008/0182954, which is incorporatedherein by reference in its entirety, provides other examples wherealuminoxanes and organoaluminum compounds can be employed incombination.

As mentioned above, alkylating agents useful in the lanthanide-basedcatalyst system can include organomagnesium compounds. In one or moreembodiments, organomagnesium compounds that can be utilized includethose represented by the general formula MgR₂, where each Rindependently can be a monovalent organic group that is attached to themagnesium atom via a carbon atom. In one or more embodiments, each Rindependently can be a hydrocarbyl group including, but not limited to,alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl,substituted cycloalkenyl, aryl, allyl, substituted aryl, aralkyl,alkaryl, and alkynyl groups, with each group containing in the range offrom 1 carbon atom, or the appropriate minimum number of carbon atoms toform the group, up to about 20 carbon atoms. These hydrocarbyl groupsmay also contain heteroatoms including, but not limited to, nitrogen,oxygen, silicon, sulfur, and phosphorus atoms.

Suitable organomagnesium compounds that may be represented by thegeneral formula MgR₂ include, but are not limited to, diethylmagnesium,di-n-propylmagnesium, diisopropylmagnesium, dibutylmagnesium,dihexylmagnesium, diphenylmagnesium, and dibenzylmagnesium.

Another class of organomagnesium compounds that can be utilized as analkylating agent may be represented by the general formula RMgX, where Rcan be a monovalent organic group that is attached to the magnesium atomvia a carbon atom, and X can be a hydrogen atom, a halogen atom, acarboxylate group, an alkoxide group, or an aryloxide group. Where thealkylating agent is an organomagnesium compound that includes a halogenatom, the organomagnesium compound can serve as both the alkylatingagent and at least a portion of the halogen source in the catalystsystems. In one or more embodiments, R can be a hydrocarbyl groupincluding, but not limited to, alkyl, cycloalkyl, substitutedcycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, aryl,allyl, substituted aryl, aralkyl, alkaryl, and alkynyl groups, with eachgroup containing in the range of from 1 carbon atom, or the appropriateminimum number of carbon atoms to form the group, up to about 20 carbonatoms. These hydrocarbyl groups may also contain heteroatoms including,but not limited to, nitrogen, oxygen, boron, silicon, sulfur, andphosphorus atoms. In one embodiment, X can be a carboxylate group, analkoxide group, or an aryloxide group, with each group containing in therange of from 1 to about 20 carbon atoms.

Types of organomagnesium compounds that may be represented by thegeneral formula RMgX include, but are not limited to,hydrocarbylmagnesium hydride, hydrocarbylmagnesium halide,hydrocarbylmagnesium carboxylate, hydrocarbylmagnesium alkoxide, andhydrocarbylmagnesium aryloxide.

Suitable organomagnesium compounds that may be represented by thegeneral formula RMgX include, but are not limited to, methylmagnesiumhydride, ethylmagnesium hydride, butylmagnesium hydride, hexylmagnesiumhydride, phenylmagnesium hydride, benzylmagnesium hydride,methylmagnesium chloride, ethylmagnesium chloride, butylmagnesiumchloride, hexylmagnesium chloride, phenylmagnesium chloride,benzylmagnesium chloride, methylmagnesium bromide, ethylmagnesiumbromide, butylmagnesium bromide, hexylmagnesium bromide, phenylmagnesiumbromide, benzylmagnesium bromide, methylmagnesium hexanoate,ethylmagnesium hexanoate, butylmagnesium hexanoate, hexylmagnesiumhexanoate, phenylmagnesium hexanoate, benzylmagnesium hexanoate,methylmagnesium ethoxide, ethylmagnesium ethoxide, butylmagnesiumethoxide, hexylmagnesium ethoxide, phenylmagnesium ethoxide,benzylmagnesium ethoxide, methylmagnesium phenoxide, ethylmagnesiumphenoxide, butylmagnesium phenoxide, hexylmagnesium phenoxide,phenylmagnesium phenoxide, and benzylmagnesium phenoxide.

As mentioned above, the lanthanide-based catalyst systems employed inthe present invention can include a halogen source. As used herein, theterm halogen source refers to any substance including at least onehalogen atom. In one or more embodiments, at least a portion of thehalogen source can be provided by either of the above-describedlanthanide-containing compound and/or the above-described alkylatingagent, when those compounds contain at least one halogen atom. In otherwords, the lanthanide-containing compound can serve as both thelanthanide-containing compound and at least a portion of the halogensource. Similarly, the alkylating agent can serve as both the alkylatingagent and at least a portion of the halogen source.

In another embodiment, at least a portion of the halogen source can bepresent in the catalyst systems in the form of a separate and distincthalogen-containing compound. Various compounds, or mixtures thereof,that contain one or more halogen atoms can be employed as the halogensource. Examples of halogen atoms include, but are not limited to,fluorine, chlorine, bromine, and iodine. A combination of two or morehalogen atoms can also be utilized. Halogen-containing compounds thatare soluble in a hydrocarbon solvent are suitable for use in the presentinvention. Hydrocarbon-insoluble halogen-containing compounds, however,can be suspended in a polymerization system to form the catalyticallyactive species, and are therefore also useful.

Useful types of halogen-containing compounds that can be employedinclude, but are not limited to, elemental halogens, mixed halogens,hydrogen halides, organic halides, inorganic halides, metallic halides,and organometallic halides.

Suitable elemental halogens include, but are not limited to, fluorine,chlorine, bromine, and iodine. Some specific examples of suitable mixedhalogens include iodine monochloride, iodine monobromide, iodinetrichloride, and iodine pentafluoride.

Suitable hydrogen halides include, but are not limited to, hydrogenfluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide.

Suitable organic halides include, but are not limited to, t-butylchloride, t-butyl bromide, allyl chloride, allyl bromide, benzylchloride, benzyl bromide, chloro-di-phenylmethane,bromo-di-phenylmethane, triphenylmethyl chloride, triphenylmethylbromide, benzylidene chloride, benzylidene bromide,methyltrichlorosilane, phenyltrichlorosilane, dimethyldichlorosilane,diphenyldichlorosilane, trimethylchlorosilane, benzoyl chloride, benzoylbromide, propionyl chloride, propionyl bromide, methyl chloroformate,and methyl bromoformate.

Suitable inorganic halides include, but are not limited to, phosphorustrichloride, phosphorus tribromide, phosphorus pentachloride, phosphorusoxychloride, phosphorus oxybromide, boron trifluoride, borontrichloride, boron tribromide, silicon tetrafluoride, silicontetrachloride, silicon tetrabromide, silicon tetraiodide, arsenictrichloride, arsenic tribromide, arsenic triiodide, seleniumtetrachloride, selenium tetrabromide, tellurium tetrachloride, telluriumtetrabromide, and tellurium tetraiodide.

Suitable metallic halides include, but are not limited to, tintetrachloride, tin tetrabromide, aluminum trichloride, aluminumtribromide, antimony trichloride, antimony pentachloride, antimonytribromide, aluminum triiodide, aluminum trifluoride, galliumtrichloride, gallium tribromide, gallium triiodide, gallium trifluoride,indium trichloride, indium tribromide, indium triiodide, indiumtrifluoride, titanium tetrachloride, titanium tetrabromide, titaniumtetraiodide, zinc dichloride, zinc dibromide, zinc diiodide, and zincdifluoride.

Suitable organometallic halides include, but are not limited to,dimethylaluminum chloride, diethylaluminum chloride, dimethylaluminumbromide, diethylaluminum bromide, dimethylaluminum fluoride,diethylaluminum fluoride, methylaluminum dichloride, ethylaluminumdichloride, methylaluminum dibromide, ethylaluminum dibromide,methylaluminum difluoride, ethylaluminum difluoride, methylaluminumsesquichloride, ethylaluminum sesquichloride, isobutylaluminumsesquichloride, methylmagnesium chloride, methylmagnesium bromide,methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide,butylmagnesium chloride, butylmagnesium bromide, phenylmagnesiumchloride, phenylmagnesium bromide, benzylmagnesium chloride,trimethyltin chloride, trimethyltin bromide, triethyltin chloride,triethyltin bromide, di-t-butyltin dichloride, di-t-butyltin dibromide,dibutyltin dichloride, dibutyltin dibromide, tributyltin chloride, andtributyltin bromide.

In one or more embodiments, the lanthanide-based catalyst systems cancomprise a compound containing a non-coordinating anion or anon-coordinating anion precursor. In one or more embodiments, a compoundcontaining a non-coordinating anion, or a non-coordinating anionprecursor can be employed in lieu of the above-described halogen source.A non-coordinating anion is a sterically bulky anion that does not formcoordinate bonds with, for example, the active center of a catalystsystem due to stearic hindrance. Non-coordinating anions useful in thepresent invention include, but are not limited to, tetraarylborateanions and fluorinated tetraarylborate anions. Compounds containing anon-coordinating anion can also contain a counter cation, such as acarbonium, ammonium, or phosphonium cation. Exemplary counter cationsinclude, but are not limited to, triarylcarbonium cations andN,N-dialkylanilinium cations. Examples of compounds containing anon-coordinating anion and a counter cation include, but are not limitedto, triphenylcarbonium tetrakis(pentafluorophenyl)borate,N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,triphenylcarbonium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, andN,N-dimethylanilinium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate.

A non-coordinating anion precursor can also be used in this embodiment.A non-coordinating anion precursor is a compound that is able to form anon-coordinating anion under reaction conditions. Usefulnon-coordinating anion precursors include, but are not limited to,triarylboron compounds, BR₃, where R is a strong electron-withdrawingaryl group, such as a pentafluorophenyl or3,5-bis(trifluoromethyl)phenyl group.

The lanthanide-based catalyst composition used in this invention may beformed by combining or mixing the foregoing catalyst ingredients.Although one or more active catalyst species are believed to result fromthe combination of the lanthanide-based catalyst ingredients, the degreeof interaction or reaction between the various catalyst ingredients orcomponents is not known with any great degree of certainty. Therefore,the term “catalyst composition” has been employed to encompass a simplemixture of the ingredients, a complex of the various ingredients that iscaused by physical or chemical forces of attraction, a chemical reactionproduct of the ingredients, or a combination of the foregoing.

The foregoing lanthanide-based catalyst composition may have highcatalytic activity for polymerizing conjugated dienes intocis-1,4-polydienes over a wide range of catalyst concentrations andcatalyst ingredient ratios. Several factors may impact the optimumconcentration of any one of the catalyst ingredients. For example,because the catalyst ingredients may interact to form an active species,the optimum concentration for any one catalyst ingredient may bedependent upon the concentrations of the other catalyst ingredients.

In one or more embodiments, the molar ratio of the alkylating agent tothe lanthanide-containing compound (alkylating agent/Ln) can be variedfrom about 1:1 to about 1,000:1, in other embodiments from about 2:1 toabout 500:1, and in other embodiments from about 5:1 to about 200:1.

In those embodiments where both an aluminoxane and at least one otherorganoaluminum agent are employed as alkylating agents, the molar ratioof the aluminoxane to the lanthanide-containing compound(aluminoxane/Ln) can be varied from 5:1 to about 1,000:1, in otherembodiments from about 10:1 to about 700:1, and in other embodimentsfrom about 20:1 to about 500:1; and the molar ratio of the at least oneother organoaluminum compound to the lanthanide-containing compound(Al/Ln) can be varied from about 1:1 to about 200:1, in otherembodiments from about 2:1 to about 150:1, and in other embodiments fromabout 5:1 to about 100:1.

The molar ratio of the halogen-containing compound to thelanthanide-containing compound is best described in terms of the ratioof the moles of halogen atoms in the halogen source to the moles oflanthanide atoms in the lanthanide-containing compound (halogen/Ln). Inone or more embodiments, the halogen/Ln molar ratio can be varied fromabout 0.5:1 to about 20:1, in other embodiments from about 1:1 to about10:1, and in other embodiments from about 2:1 to about 6:1.

In yet another embodiment, the molar ratio of the non-coordinating anionor non-coordinating anion precursor to the lanthanide-containingcompound (An/Ln) may be from about 0.5:1 to about 20:1, in otherembodiments from about 0.75:1 to about 10:1, and in other embodimentsfrom about 1:1 to about 6:1.

The lanthanide-based catalyst composition can be formed by variousmethods.

In one embodiment, the lanthanide-based catalyst composition may beformed in situ by adding the catalyst ingredients to a solutioncontaining monomer and solvent, or to bulk monomer, in either a stepwiseor simultaneous manner. In one embodiment, the alkylating agent can beadded first, followed by the lanthanide-containing compound, and thenfollowed by the halogen source or by the compound containing anon-coordinating anion or the non-coordinating anion precursor.

In another embodiment, the lanthanide-based catalyst composition may bepreformed. That is, the catalyst ingredients are pre-mixed outside thepolymerization system either in the absence of any monomer or in thepresence of a small amount of at least one conjugated diene monomer atan appropriate temperature, which may be from about −20° C. to about 80°C. The amount of conjugated diene monomer that may be used forpreforming the catalyst can range from about 1 to about 500 moles, inother embodiments from about 5 to about 250 moles, and in otherembodiments from about 10 to about 100 moles per mole of thelanthanide-containing compound. The resulting catalyst composition maybe aged, if desired, prior to being added to the monomer that is to bepolymerized.

In yet another embodiment, the lanthanide-based catalyst composition maybe formed by using a two-stage procedure. The first stage may involvecombining the alkylating agent with the lanthanide-containing compoundeither in the absence of any monomer or in the presence of a smallamount of at least one conjugated diene monomer at an appropriatetemperature, which may be from about −20° C. to about 80° C. The amountof monomer employed in the first stage may be similar to that set forthabove for preforming the catalyst. In the second stage, the mixtureformed in the first stage and the halogen source, non-coordinatinganion, or non-coordinating anion precursor can be charged in either astepwise or simultaneous manner to the monomer that is to bepolymerized.

In one or more embodiments, the reactive polymer is prepared by anionicpolymerization, wherein monomer is polymerized by using an anionicinitiator. The key mechanistic features of anionic polymerization havebeen described in books (e.g., Hsieh, H. L.; Quirk, R. P. AnionicPolymerization: Principles and Practical Applications; Marcel Dekker:New York, 1996) and review articles (e.g., Hadjichristidis, N.;Pitsikalis, M.; Pispas, S.; Iatrou, H.; Chem. Rev. 2001, 101(12),3747-3792). Anionic initiators may advantageously produce livingpolymers that, prior to quenching, are capable of reacting withadditional monomer for further chain growth or reacting with certainfunctionalizing agents to give functionalized polymers.

The practice of this invention is not limited by the selection of anyparticular anionic initiators. In one or more embodiments, the anionicinitiator employed is a functional initiator that imparts a functionalgroup at the head of the polymer chain (i.e., the location from whichthe polymer chain is started). In particular embodiments, the functionalgroup includes one or more heteroatoms (e.g., nitrogen, oxygen, boron,silicon, sulfur, tin, and phosphorus atoms) or heterocyclic groups. Incertain embodiments, the functional group reduces the 50° C. hysteresisloss of carbon-black filled vulcanizates prepared from polymerscontaining the functional group as compared to similar carbon-blackfilled vulcanizates prepared from polymer that does not include thefunctional group.

Exemplary anionic initiators include organolithium compounds. In one ormore embodiments, organolithium compounds may include heteroatoms. Inthese or other embodiments, organolithium compounds may include one ormore heterocyclic groups.

Types of organolithium compounds include alkyllithium, aryllithiumcompounds, and cycloalkyllithium compounds. Specific examples oforganolithium compounds include ethyllithium, n-propyllithium,isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium,n-amyllithium, isoamyllithium, and phenyllithium.

Other anionic initiators include alkylmagnesium halide compounds such asbutylmagnesium bromide and phenylmagnesium bromide. Still other anionicinitiators include organosodium compounds such as phenylsodium and2,4,6-trimethylphenylsodium. Also contemplated are those anionicinitiators that give rise to di-living polymers, wherein both ends of apolymer chain are living. Examples of such initiators include dilithioinitiators such as those prepared by reacting 1,3-diisopropenylbenzenewith sec-butyllithium. These and related difunctional initiators aredisclosed in U.S. Pat. No. 3,652,516, which is incorporated herein byreference. Radical anionic initiators may also be employed, includingthose described in U.S. Pat. No. 5,552,483, which is incorporated hereinby reference.

In particular embodiments, the organolithium compounds include a cyclicamine-containing compound such as lithiohexamethyleneimine. These andrelated useful initiators are disclosed in the U.S. Pat. Nos. 5,332,810,5,329,005, 5,578,542, 5,393,721, 5,698,646, 5,491,230, 5,521,309,5,496,940, 5,574,109, and 5,786,441, which are incorporated herein byreference. In other embodiments, the organolithium compounds includelithiated alkylthioacetals such as 2-lithio-2-methyl-1,3-dithiane. Theseand related useful initiators are disclosed in U.S. Publ. Nos.2006/0030657, 2006/0264590, and 2006/0264589, which are incorporatedherein by reference. In still other embodiments, the organolithiumcompounds include alkoxysilyl-containing initiators, such as lithiatedt-butyldimethylpropoxysilane. These and related useful initiators aredisclosed in U.S. Publ. No. 2006/0241241, which is incorporated hereinby reference.

In one or more embodiments, the anionic initiator employed istrialkyltinlithium compound such as tri-n-butyltinlithium. These andrelated useful initiators are disclosed in U.S. Pat. Nos. 3,426,006 and5,268,439, which are incorporated herein by reference.

When elastomeric copolymers containing conjugated diene monomer andvinyl-substituted aromatic monomer are prepared by anionicpolymerization, the conjugated diene monomer and vinyl-substitutedaromatic monomer may be used at a weight ratio of 95:5 to 50:50, or inother embodiments, 90:10 to 65:35. In order to promote the randomizationof comonomers in copolymerization and to control the microstructure(such as 1,2-linkage of conjugated diene monomer) of the polymer, arandomizer, which is typically a polar coordinator, may be employedalong with the anionic initiator.

Compounds useful as randomizers include those having an oxygen ornitrogen heteroatom and a non-bonded pair of electrons. Exemplary typesof randomizers include linear and cyclic oligomeric oxolanyl alkanes;dialkyl ethers of mono and oligo alkylene glycols (also known as glymeethers); crown ethers; tertiary amines; linear THF oligomers; alkalimetal alkoxides; and alkali metal sulfonates. Linear and cyclicoligomeric oxolanyl alkanes are described in U.S. Pat. No. 4,429,091,which is incorporated herein by reference. Specific examples ofrandomizers include 2,2-bis(2′-tetrahydrofuryl)propane,1,2-dimethoxyethane, N,N,N′,N′-tetramethylethylenediamine (TMEDA),tetrahydrofuran (THF), 1,2-dipiperidylethane, dipiperidylmethane,hexamethylphosphoramide, N,N′-dimethylpiperazine, diazabicyclooctane,dimethyl ether, diethyl ether, tri-n-butylamine, potassium t-amylate,potassium 4-dodecylsulfonate, and mixtures thereof.

The amount of randomizer to be employed may depend on various factorssuch as the desired microstructure of the polymer, the ratio of monomerto comonomer, the polymerization temperature, as well as the nature ofthe specific randomizer employed. In one or more embodiments, the amountof randomizer employed may range between 0.05 and 100 moles per mole ofthe anionic initiator.

The anionic initiator and the randomizer can be introduced to thepolymerization system by various methods. In one or more embodiments,the anionic initiator and the randomizer may be added separately to themonomer to be polymerized in either a stepwise or simultaneous manner.In other embodiments, the anionic initiator and the randomizer may bepre-mixed outside the polymerization system either in the absence of anymonomer or in the presence of a small amount of monomer, and theresulting mixture may be aged, if desired, and then added to the monomerthat is to be polymerized.

In one or more embodiments, regardless of whether a coordinationcatalyst or an anionic initiator is used to prepare the reactivepolymer, a solvent may be employed as a carrier to either dissolve orsuspend the catalyst or initiator in order to facilitate the delivery ofthe catalyst or initiator to the polymerization system. In otherembodiments, monomer can be used as the carrier. In yet otherembodiments, the catalyst or initiator can be used in their neat statewithout any solvent.

In one or more embodiments, suitable solvents include those organiccompounds that will not undergo polymerization or incorporation intopropagating polymer chains during the polymerization of monomer in thepresence of the catalyst or initiator. In one or more embodiments, theseorganic species are liquid at ambient temperature and pressure. In oneor more embodiments, these organic solvents are inert to the catalyst orinitiator. Exemplary organic solvents include hydrocarbons with a low orrelatively low boiling point such as aromatic hydrocarbons, aliphatichydrocarbons, and cycloaliphatic hydrocarbons. Non-limiting examples ofaromatic hydrocarbons include benzene, toluene, xylenes, ethylbenzene,diethylbenzene, and mesitylene. Non-limiting examples of aliphatichydrocarbons include n-pentane, n-hexane, n-heptane, n-octane, n-nonane,n-decane, isopentane, isohexanes, isopentanes, isooctanes,2,2-dimethylbutane, petroleum ether, kerosene, and petroleum spirits.And, non-limiting examples of cycloaliphatic hydrocarbons includecyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane.Mixtures of the above hydrocarbons may also be used. As is known in theart, aliphatic and cycloaliphatic hydrocarbons may be desirably employedfor environmental reasons. The low-boiling hydrocarbon solvents aretypically separated from the polymer upon completion of thepolymerization.

Other examples of organic solvents include high-boiling hydrocarbons ofhigh molecular weights, including hydrocarbon oils that are commonlyused to oil-extend polymers. Examples of these oils include paraffinicoils, aromatic oils, naphthenic oils, vegetable oils other than castoroils, and low PCA oils including MES, TDAE, SRAE, heavy naphthenic oils.Since these hydrocarbons are non-volatile, they typically do not requireseparation and remain incorporated in the polymer.

The production of the reactive polymer according to this invention canbe accomplished by polymerizing conjugated diene monomer, optionallytogether with monomer copolymerizable with conjugated diene monomer, inthe presence of a catalytically effective amount of the catalyst orinitiator. The introduction of the catalyst or initiator, the conjugateddiene monomer, optionally the comonomer, and any solvent, if employed,forms a polymerization mixture in which the reactive polymer is formed.The amount of the catalyst or initiator to be employed may depend on theinterplay of various factors such as the type of catalyst or initiatoremployed, the purity of the ingredients, the polymerization temperature,the polymerization rate and conversion desired, the molecular weightdesired, and many other factors. Accordingly, a specific catalyst orinitiator amount cannot be definitively set forth except to say thatcatalytically effective amounts of the catalyst or initiator may beused.

In one or more embodiments, the amount of the coordinating metalcompound (e.g., a lanthanide-containing compound) used can be variedfrom about 0.001 to about 2 mmol, in other embodiments from about 0.005to about 1 mmol, and in still other embodiments from about 0.01 to about0.2 mmol per 100 gram of monomer.

In other embodiments, where an anionic initiator (e.g., an alkyllithiumcompound) is employed, the initiator loading may be varied from about0.05 to about 100 mmol, in other embodiments from about 0.1 to about 50mmol, and in still other embodiments from about 0.2 to about 5 mmol per100 gram of monomer.

In one or more embodiments, the polymerization may be carried out in apolymerization system that includes a substantial amount of solvent. Inone embodiment, a solution polymerization system may be employed inwhich both the monomer to be polymerized and the polymer formed aresoluble in the solvent. In another embodiment, a precipitationpolymerization system may be employed by choosing a solvent in which thepolymer formed is insoluble. In both cases, an amount of solvent inaddition to the amount of solvent that may be used in preparing thecatalyst or initiator is usually added to the polymerization system. Theadditional solvent may be the same as or different from the solvent usedin preparing the catalyst or initiator. Exemplary solvents have been setforth above. In one or more embodiments, the solvent content of thepolymerization mixture may be more than 20% by weight, in otherembodiments more than 50% by weight, and in still other embodiments morethan 80% by weight based on the total weight of the polymerizationmixture.

In other embodiments, the polymerization system employed may begenerally considered a bulk polymerization system that includessubstantially no solvent or a minimal amount of solvent. Those skilledin the art will appreciate the benefits of bulk polymerization processes(i.e., processes where monomer acts as the solvent), and therefore thepolymerization system includes less solvent than will deleteriouslyimpact the benefits sought by conducting bulk polymerization. In one ormore embodiments, the solvent content of the polymerization mixture maybe less than about 20% by weight, in other embodiments less than about10% by weight, and in still other embodiments less than about 5% byweight based on the total weight of the polymerization mixture. Inanother embodiment, the polymerization mixture contains no solventsother than those that are inherent to the raw materials employed. Instill another embodiment, the polymerization mixture is substantiallydevoid of solvent, which refers to the absence of that amount of solventthat would otherwise have an appreciable impact on the polymerizationprocess. Polymerization systems that are substantially devoid of solventmay be referred to as including substantially no solvent. In particularembodiments, the polymerization mixture is devoid of solvent.

The polymerization may be conducted in any conventional polymerizationvessels known in the art. In one or more embodiments, solutionpolymerization can be conducted in a conventional stirred-tank reactor.In other embodiments, bulk polymerization can be conducted in aconventional stirred-tank reactor, especially if the monomer conversionis less than about 60%. In still other embodiments, especially where themonomer conversion in a bulk polymerization process is higher than about60%, which typically results in a highly viscous cement, the bulkpolymerization may be conducted in an elongated reactor in which theviscous cement under polymerization is driven to move by piston, orsubstantially by piston. For example, extruders in which the cement ispushed along by a self-cleaning single-screw or double-screw agitatorare suitable for this purpose. Examples of useful bulk polymerizationprocesses are disclosed in U.S. Pat. No. 7,351,776, which isincorporated herein by reference.

In one or more embodiments, all of the ingredients used for thepolymerization can be combined within a single vessel (e.g., aconventional stirred-tank reactor), and all steps of the polymerizationprocess can be conducted within this vessel. In other embodiments, twoor more of the ingredients can be pre-combined in one vessel and thentransferred to another vessel where the polymerization of monomer (or atleast a major portion thereof) may be conducted.

The polymerization can be carried out as a batch process, a continuousprocess, or a semi-continuous process. In the semi-continuous process,the monomer is intermittently charged as needed to replace that monomeralready polymerized. In one or more embodiments, the conditions underwhich the polymerization proceeds may be controlled to maintain thetemperature of the polymerization mixture within a range from about −10°C. to about 200° C., in other embodiments from about 0° C. to about 150°C., and in other embodiments from about 20° C. to about 100° C. In oneor more embodiments, the heat of polymerization may be removed byexternal cooling by a thermally controlled reactor jacket, internalcooling by evaporation and condensation of the monomer through the useof a reflux condenser connected to the reactor, or a combination of thetwo methods. Also, the polymerization conditions may be controlled toconduct the polymerization under a pressure of from about 0.1 atmosphereto about 50 atmospheres, in other embodiments from about 0.5 atmosphereto about 20 atmosphere, and in other embodiments from about 1 atmosphereto about 10 atmospheres. In one or more embodiments, the pressures atwhich the polymerization may be carried out include those that ensurethat the majority of the monomer is in the liquid phase. In these orother embodiments, the polymerization mixture may be maintained underanaerobic conditions.

Regardless of whether the polymerization is catalyzed or initiated by acoordination catalyst (e.g., a lanthanide-based catalyst) or an anionicinitiator (e.g., an alkyllithium initiator), some or all of theresulting polymer chains may possess reactive chain ends before thepolymerization mixture is quenched. Thus, reference to a reactivepolymer refers to a polymer having a reactive chain end deriving from asynthesis of the polymer by using a coordination catalyst or an anionicinitiator. As noted above, the reactive polymer prepared with acoordination catalyst (e.g., a lanthanide-based catalyst) may bereferred to as a pseudo-living polymer, and the reactive polymerprepared with an anionic initiator (e.g., an alkyllithium initiator) maybe referred to as a living polymer. In one or more embodiments, apolymerization mixture including reactive polymer may be referred to asan active polymerization mixture. The percentage of polymer chainspossessing a reactive end depends on various factors such as the type ofcatalyst or initiator, the type of monomer, the purity of theingredients, the polymerization temperature, the monomer conversion, andmany other factors. In one or more embodiments, at least about 20% ofthe polymer chains possess a reactive end, in other embodiments at leastabout 50% of the polymer chains possess a reactive end, and in stillother embodiments at least about 80% of the polymer chains possess areactive end. In any event, the reactive polymer can be reacted with anazodiester to form the functionalized polymer of this invention.

In one or more embodiments, azodiesters may include those compounds thatcontain an azo group and two ester groups. In one or more embodiments,the azodiesters contain an azo group wherein each nitrogen atom of theazo group is bonded to an ester group. In one or more embodiments, theazodiesters contain an azo group that may be bonded to the carbon atomof the carbonyl group on each of the two ester groups.

In one or more embodiments, the azo group may be defined by the formula—N═N—.

In one or more embodiments, the ester group may be defined by theformula:

where R¹ is a monovalent organic group, and each α is independently anoxygen atom or a sulfur atom. As those skilled in the art appreciate,where both α atoms are oxygen atoms, the ester group may be referred toas a carboxylic ester group. Where one or both α atoms are sulfur atoms,the ester group may be referred to as a thiocarboxylic ester group. Morespecifically, where one a atom is a sulfur atom (either α atom) and theother a atom is an oxygen atom, the ester group may be referred to as amonothiocarboxylic ester group. Where both α atoms are sulfur atoms, theester group may be referred to as a dithiocarboxylic ester group. Forpurposes of this specification, reference to a thiocarboxylic estergroup may encompass both monothiocarboxylic ester groups anddithiocarboxylic ester groups. For ease of explanation, carboxylic andthiocarboxylic ester groups may be referred to collectively as estergroups.

In one or more embodiments, an azodiester may be defined by the formulaI:

where R¹ and R² are each independently a monovalent organic group, andeach α is independently an oxygen atom or a sulfur atom.

In one or more embodiments, where the R¹ of formula I is a silyl group,the azodiester may be defined by the formula II:

where R² is a monovalent organic group, R³, R⁴, and R⁵ are eachindependently a hydrogen atom or a monovalent organic group, and each αis independently an oxygen atom or a sulfur atom.

In one or more embodiments, where the R¹ and R² of formula 1 are silylgroups, the azodiester may be defined by the formula III:

where R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are each independently a hydrogen atomor a monovalent organic group, and each α is independently an oxygenatom or a sulfur atom.

In one or more embodiments, the monovalent organic groups of theazodiesters may be hydrocarbyl groups such as, but not limited to,alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, allyl, aralkyl, alkaryl,or alkynyl groups. Hydrocarbyl groups also include substitutedhydrocarbyl groups, which refer to hydrocarbyl groups in which one ormore hydrogen atoms have been replaced by a substituent such as ahydrocarbyl, hydrocarbyloxy, silyl, or silyloxy group. In one or moreembodiments, these groups may include from one, or the appropriateminimum number of carbon atoms to form the group, to about 20 carbonatoms. These groups may also contain heteroatoms such as, but notlimited to, nitrogen, boron, oxygen, silicon, sulfur, tin, andphosphorus atoms.

In one or more embodiments, the monovalent organic groups of theazodiesters may be silyl groups such as, but not limited to,trihydrocarbylsilyl, dihydrocarbylhydrosilyl, orhydrocarbyldihydrosilyl. Silyl groups also include substituted silylgroups, which refer to silyl groups in which one or more hydrogen atomshave been replaced by a substituent such as a hydrocarbyl,hydrocarbyloxy, silyl, or silyloxy group. In one or more embodiments,these groups may include from one, or the appropriate minimum number ofcarbon atoms to form the group, to about 20 carbon atoms. These groupsmay include heteroatoms such as, but not limited to, nitrogen, boron,oxygen, silicon, sulfur, tin, and phosphorus atoms, in addition to theparent silicon atom.

In one or more embodiments, the monovalent organic groups of theazodiesters may contain one or more ester groups. For example, an estergroup may be pendently attached to R¹ or R² of formula I. In theseembodiments, the azodiesters may contain three or more ester groups.

In one or more embodiments, where R¹ and R² of formula I are hydrocarbylgroups and each α is an oxygen atom, the azodiester may be referred toas a dihydrocarbyl azodicarboxylate. In other embodiments, where R¹ andR² of formula I are trihydrocarbylsilyl groups and each α is an oxygenatom, the azodiester may be referred to as abis(trihydrocarbylsilyl)azodicarboxylate. In other embodiments, where R¹and R² of formula I are dihydrocarbylhydrosilyl groups and each α is anoxygen atom, the azodiester may be referred to as abis(dihydrocarbylhydrosilyl)azodicarboxylate. In other embodiments,where the R¹ of formula I is a trihydrocarbylsilyl group, the R² offormula I is a hydrocarbyl group, and each α is an oxygen atom, theazodiester may be referred to as a trihydrocarbylsilyl hydrocarbylazodicarboxylate. In other embodiments, where the R¹ of formula I is adihydrocarbylhydrosilyl group, the R² of formula I is a hydrocarbylgroup, and each α is an oxygen atom, the azodiester may be referred toas a dihydrocarbylhydrosilyl hydrocarbyl azodicarboxylate.

In one or more embodiments, where R¹ and R² of formula I are hydrocarbylgroups and one or more α atoms are sulfur atoms, the azodiester may bereferred to as a dihydrocarbyl azothiodicarboxylate. In otherembodiments, where R¹ and R² of formula I are trihydrocarbylsilyl groupsand one or more α atoms are sulfur atoms, the azodiester may be referredto as a bis(trihydrocarbylsilyl)azothiodicarboxylate. In otherembodiments, where R¹ and R² of formula I are dihydrocarbylhydrosilylgroups and one or more α atoms are sulfur atoms, the azodiester may bereferred to as a bis(dihydrocarbylhydrosilyl)azothiodicarboxylate. Inother embodiments, where the R¹ of formula I is a trihydrocarbylsilylgroup, the R² of formula I is a hydrocarbyl group, and one or more αatoms are sulfur atoms, the azodiester may be referred to as atrihydrocarbylsilyl hydrocarbyl azothiodicarboxylate. In otherembodiments, where the R¹ of formula I is a dihydrocarbylhydrosilylgroup, the R² of formula I is a hydrocarbyl group, and one or more αatoms are sulfur atoms, the azodiester may be referred to as adihydrocarbylhydrosilyl hydrocarbyl azothiodicarboxylate.

Specific examples of dihydrocarbyl azodicarboxylates include dimethylazodicarboxylate, diethyl azodicarboxylate, di-n-propylazodicarboxylate, diisopropyl azodicarboxylate, di-n-butylazodicarboxylate, diisobutyl azodicarboxylate, di-t-butylazodicarboxylate, di-n-pentyl azodicarboxylate, di-n-hexylazodicarboxylate, di-n-heptyl azodicarboxylate, di-n-octylazodicarboxylate, dicyclopentyl azodicarboxylate, dicyclohexylazodicarboxylate, dibenzyl azodicarboxylate, diphenyl azodicarboxylate,di-o-tolyl azodicarboxylate, di-m-tolyl azodicarboxylate, di-p-tolylazodicarboxylate, bis(2-ethylhexyl)azodicarboxylate, methyl ethylazodicarboxylate, methyl n-propyl azodicarboxylate, ethyl n-propylazodicarboxylate, methyl isopropyl azodicarboxylate, ethyl isopropylazodicarboxylate, n-propyl isopropyl azodicarboxylate, methyl n-butylazodicarboxylate, ethyl n-butyl azodicarboxylate, n-propyl n-butylazodicarboxylate, isopropyl n-butyl azodicarboxylate, methyl isobutylazodicarboxylate, ethyl isobutyl azodicarboxylate, n-propyl isobutylazodicarboxylate, isopropyl isobutyl azodicarboxylate, n-butyl isobutylazodicarboxylate, methyl t-butyl azodicarboxylate, ethyl t-butylazodicarboxylate, n-propyl t-butyl azodicarboxylate, isopropyl t-butylazodicarboxylate, n-butyl t-butyl azodicarboxylate, isobutyl t-butylazodicarboxylate, methyl n-pentyl azodicarboxylate, ethyl n-pentylazodicarboxylate, n-propyl n-pentyl azodicarboxylate, isopropyl n-pentylazodicarboxylate, n-butyl n-pentyl azodicarboxylate, isobutyl n-pentylazodicarboxylate, t-butyl n-pentyl azodicarboxylate, methyl n-hexylazodicarboxylate, ethyl n-hexyl azodicarboxylate, n-propyl n-hexylazodicarboxylate, isopropyl n-hexyl azodicarboxylate, n-butyl n-hexylazodicarboxylate, isobutyl n-hexyl azodicarboxylate, t-butyl n-hexylazodicarboxylate, n-pentyl n-hexyl azodicarboxylate, methyl n-heptylazodicarboxylate, ethyl n-heptyl azodicarboxylate, n-propyl n-heptylazodicarboxylate, isopropyl n-heptyl azodicarboxylate, n-butyl n-heptylazodicarboxylate, isobutyl n-heptyl azodicarboxylate, t-butyl n-heptylazodicarboxylate, n-pentyl n-heptyl azodicarboxylate, n-hexyl n-heptylazodicarboxylate, methyl n-octyl azodicarboxylate, ethyl n-octylazodicarboxylate, n-propyl n-octyl azodicarboxylate, isopropyl n-octylazodicarboxylate, n-butyl n-octyl azodicarboxylate, isobutyl n-octylazodicarboxylate, t-butyl n-octyl azodicarboxylate, n-pentyl n-octylazodicarboxylate, n-hexyl n-octyl azodicarboxylate, n-heptyl n-octylazodicarboxylate, methyl cyclopentyl azodicarboxylate, ethyl cyclopentylazodicarboxylate, n-propyl cyclopentyl azodicarboxylate, isopropylcyclopentyl azodicarboxylate, n-butyl cyclopentyl azodicarboxylate,isobutyl cyclopentyl azodicarboxylate, t-butyl cyclopentylazodicarboxylate, n-pentyl cyclopentyl azodicarboxylate, n-hexylcyclopentyl azodicarboxylate, n-heptyl cyclopentyl azodicarboxylate,n-octyl cyclopentyl azodicarboxylate, methyl cyclohexylazodicarboxylate, ethyl cyclohexyl azodicarboxylate, n-propyl cyclohexylazodicarboxylate, isopropyl cyclohexyl azodicarboxylate, n-butylcyclohexyl azodicarboxylate, isobutyl cyclohexyl azodicarboxylate,t-butyl cyclohexyl azodicarboxylate, n-pentyl cyclohexylazodicarboxylate, n-hexyl cyclohexyl azodicarboxylate, n-heptylcyclohexyl azodicarboxylate, n-octyl cyclohexyl azodicarboxylate,cyclopentyl cyclohexyl azodicarboxylate, methyl benzyl azodicarboxylate,ethyl benzyl azodicarboxylate, n-propyl benzyl azodicarboxylate,isopropyl benzyl azodicarboxylate, n-butyl benzyl azodicarboxylate,isobutyl benzyl azodicarboxylate, t-butyl benzyl azodicarboxylate,n-pentyl benzyl azodicarboxylate, n-hexyl benzyl azodicarboxylate,n-heptyl benzyl azodicarboxylate, n-octyl benzyl azodicarboxylate,cyclopentyl benzyl azodicarboxylate, cyclohexyl benzyl azodicarboxylate,methyl phenyl azodicarboxylate, ethyl phenyl azodicarboxylate, n-propylphenyl azodicarboxylate, isopropyl phenyl azodicarboxylate, n-butylphenyl azodicarboxylate, isobutyl phenyl azodicarboxylate, t-butylphenyl azodicarboxylate, n-pentyl phenyl azodicarboxylate, n-hexylphenyl azodicarboxylate, n-heptyl phenyl azodicarboxylate, n-octylphenyl azodicarboxylate, cyclopentyl phenyl azodicarboxylate, cyclohexylphenyl azodicarboxylate, benzyl phenyl azodicarboxylate, methyl o-tolylazodicarboxylate, ethyl o-tolyl azodicarboxylate, n-propyl o-tolylazodicarboxylate, isopropyl o-tolyl azodicarboxylate, n-butyl o-tolylazodicarboxylate, isobutyl o-tolyl azodicarboxylate, t-butyl o-tolylazodicarboxylate, n-pentyl o-tolyl azodicarboxylate, n-hexyl o-tolylazodicarboxylate, n-heptyl o-tolyl azodicarboxylate, n-octyl o-tolylazodicarboxylate, cyclopentyl o-tolyl azodicarboxylate, cyclohexylo-tolyl azodicarboxylate, benzyl o-tolyl azodicarboxylate, phenylo-tolyl azodicarboxylate, methyl m-tolyl azodicarboxylate, ethyl m-tolylazodicarboxylate, n-propyl m-tolyl azodicarboxylate, isopropyl m-tolylazodicarboxylate, n-butyl m-tolyl azodicarboxylate, isobutyl m-tolylazodicarboxylate, t-butyl m-tolyl azodicarboxylate, n-pentyl m-tolylazodicarboxylate, n-hexyl m-tolyl azodicarboxylate, n-heptyl m-tolylazodicarboxylate, n-octyl m-tolyl azodicarboxylate, cyclopentyl m-tolylazodicarboxylate, cyclohexyl m-tolyl azodicarboxylate, benzyl m-tolylazodicarboxylate, phenyl m-tolyl azodicarboxylate, o-tolyl m-tolylazodicarboxylate, methyl p-tolyl azodicarboxylate, ethyl p-tolylazodicarboxylate, n-propyl p-tolyl azodicarboxylate, isopropyl p-tolylazodicarboxylate, n-butyl p-tolyl azodicarboxylate, isobutyl p-tolylazodicarboxylate, t-butyl p-tolyl azodicarboxylate, n-pentyl p-tolylazodicarboxylate, n-hexyl p-tolyl azodicarboxylate, n-heptyl p-tolylazodicarboxylate, n-octyl p-tolyl azodicarboxylate, cyclopentyl p-tolylazodicarboxylate, cyclohexyl p-tolyl azodicarboxylate, benzyl p-tolylazodicarboxylate, phenyl p-tolyl azodicarboxylate, o-tolyl p-tolylazodicarboxylate, m-tolyl p-tolyl azodicarboxylate, methyl 2-ethylhexylazodicarboxylate, ethyl 2-ethylhexyl azodicarboxylate, n-propyl2-ethylhexyl azodicarboxylate, isopropyl 2-ethylhexyl azodicarboxylate,n-butyl 2-ethylhexyl azodicarboxylate, isobutyl 2-ethylhexylazodicarboxylate, t-butyl 2-ethylhexyl azodicarboxylate, n-pentyl2-ethylhexyl azodicarboxylate, n-hexyl 2-ethylhexyl azodicarboxylate,n-heptyl 2-ethylhexyl azodicarboxylate, n-octyl 2-ethylhexylazodicarboxylate, cyclopentyl 2-ethylhexyl azodicarboxylate, cyclohexyl2-ethylhexyl azodicarboxylate, benzyl 2-ethylhexyl azodicarboxylate,phenyl 2-ethylhexyl azodicarboxylate, o-tolyl 2-ethylhexylazodicarboxylate, m-tolyl 2-ethylhexyl azodicarboxylate, and p-tolyl2-ethylhexyl azodicarboxylate.

Specific examples of bis(trihydrocarbylsilyl)azodicarboxylates includebis(trimethylsilyl)azodicarboxylate, bis(triethylsilyl)azodicarboxylate,bis(triisopropylsilyl)azodicarboxylate,bis(tri-n-propylsilyl)azodicarboxylate,bis(triisobutylsilyl)azodicarboxylate,bis(tri-t-butylsilyl)azodicarboxylate,bis(triphenylsilyl)azodicarboxylate, trimethylsilyl triethylsilylazodicarboxylate, trimethylsilyl triisopropylsilyl azodicarboxylate,triethylsilyl triisopropylsilyl azodicarboxylate, trimethylsilyltri-n-propylsilyl azodicarboxylate, triethylsilyl tri-n-propylsilylazodicarboxylate, triisopropylsilyl tri-n-propylsilyl azodicarboxylate,trimethylsilyl triisobutylsilyl azodicarboxylate, triethylsilyltriisobutylsilyl azodicarboxylate, triisopropylsilyl triisobutylsilylazodicarboxylate, tri-n-propylsilyl triisobutylsilyl azodicarboxylate,trimethylsilyl tri-t-butylsilyl azodicarboxylate, triethylsilyltri-t-butylsilyl azodicarboxylate, triisopropylsilyl tri-t-butylsilylazodicarboxylate, tri-n-propylsilyl tri-t-butylsilyl azodicarboxylate,triisobutylsilyl tri-t-butylsilyl azodicarboxylate, trimethylsilyltriphenylsilyl azodicarboxylate, triethylsilyl triphenylsilylazodicarboxylate, triisopropylsilyl triphenylsilyl azodicarboxylate,tri-n-propylsilyl triphenylsilyl azodicarboxylate, triisobutylsilyltriphenylsilyl azodicarboxylate, and tri-t-butylsilyl triphenylsilylazodicarboxylate.

Specific examples of bis(dihydrocarbylhydrosilyl)azodicarboxylatesinclude bis(dimethylhydrosilyl)azodicarboxylate,bis(diethylhydrosilyl)azodicarboxylate,bis(diisopropylhydrosilyl)azodicarboxylate,bis(di-n-propylhydrosilyl)azodicarboxylate,bis(di-t-butylhydrosilyl)azodicarboxylate,bis(diphenylhydrosilyl)azodicarboxylate, dimethylhydrosilyldiethylhydrosilyl azodicarboxylate, dimethylhydrosilyldiisopropylhydrosilyl azodicarboxylate, diethylhydrosilyldiisopropylhydrosilyl azodicarboxylate, dimethylhydrosilyldi-n-propylhydrosilyl azodicarboxylate, diethylhydrosilyldi-n-propylhydrosilyl azodicarboxylate, diisopropylhydrosilyldi-n-propylhydrosilyl azodicarboxylate, dimethylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, diethylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, diisopropylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, di-n-propylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, dimethylhydrosilyldiphenylhydrosilyl azodicarboxylate, diethylhydrosilyldiphenylhydrosilyl azodicarboxylate, diisopropylhydrosilyldiphenylhydrosilyl azodicarboxylate, di-n-propylhydrosilyldiphenylhydrosilyl azodicarboxylate, and di-t-butylhydrosilyldiphenylhydrosilyl azodicarboxylate.

Specific examples of trihydrocarbylsilyl hydrocarbyl azodicarboxylatesinclude trimethylsilyl methyl azodicarboxylate, triethylsilyl methylazodicarboxylate, triisopropylsilyl methyl azodicarboxylate,tri-n-propylsilyl methyl azodicarboxylate, triisobutylsilyl methylazodicarboxylate, tri-t-butylsilyl methyl azodicarboxylate,triphenylsilyl methyl azodicarboxylate, trimethylsilyl ethylazodicarboxylate, triethylsilyl ethyl azodicarboxylate,triisopropylsilyl ethyl azodicarboxylate, tri-n-propylsilyl ethylazodicarboxylate, triisobutylsilyl ethyl azodicarboxylate,tri-t-butylsilyl ethyl azodicarboxylate, triphenylsilyl ethylazodicarboxylate, trimethylsilyl n-propyl azodicarboxylate,triethylsilyl n-propyl azodicarboxylate, triisopropylsilyl n-propylazodicarboxylate, tri-n-propylsilyl n-propyl azodicarboxylate,triisobutylsilyl n-propyl azodicarboxylate, tri-t-butylsilyl n-propylazodicarboxylate, triphenylsilyl n-propyl azodicarboxylate,trimethylsilyl isopropyl azodicarboxylate, triethylsilyl isopropylazodicarboxylate, triisopropylsilyl isopropyl azodicarboxylate,tri-n-propylsilyl isopropyl azodicarboxylate, triisobutylsilyl isopropylazodicarboxylate, tri-t-butylsilyl isopropyl azodicarboxylate,triphenylsilyl isopropyl azodicarboxylate, trimethylsilyl n-butylazodicarboxylate, triethylsilyl n-butyl azodicarboxylate,triisopropylsilyl n-butyl azodicarboxylate, tri-n-propylsilyl n-butylazodicarboxylate, triisobutylsilyl n-butyl azodicarboxylate,tri-t-butylsilyl n-butyl azodicarboxylate, triphenylsilyl n-butylazodicarboxylate, trimethylsilyl isobutyl azodicarboxylate,triethylsilyl isobutyl azodicarboxylate, triisopropylsilyl isobutylazodicarboxylate, tri-n-propylsilyl isobutyl azodicarboxylate,triisobutylsilyl isobutyl azodicarboxylate, tri-t-butylsilyl isobutylazodicarboxylate, triphenylsilyl isobutyl azodicarboxylate,trimethylsilyl t-butyl azodicarboxylate, triethylsilyl t-butylazodicarboxylate, triisopropylsilyl t-butyl azodicarboxylate,tri-n-propylsilyl t-butyl azodicarboxylate, triisobutylsilyl t-butylazodicarboxylate, tri-t-butylsilyl t-butyl azodicarboxylate,triphenylsilyl t-butyl azodicarboxylate, trimethylsilyl n-pentylazodicarboxylate, triethylsilyl n-pentyl azodicarboxylate,triisopropylsilyl n-pentyl azodicarboxylate, tri-n-propylsilyl n-pentylazodicarboxylate, triisobutylsilyl n-pentyl azodicarboxylate,tri-t-butylsilyl n-pentyl azodicarboxylate, triphenylsilyl n-pentylazodicarboxylate, trimethylsilyl n-hexyl azodicarboxylate, triethylsilyln-hexyl azodicarboxylate, triisopropylsilyl n-hexyl azodicarboxylate,tri-n-propylsilyl n-hexyl azodicarboxylate, triisobutylsilyl n-hexylazodicarboxylate, tri-t-butylsilyl n-hexyl azodicarboxylate,triphenylsilyl n-hexyl azodicarboxylate, trimethylsilyl n-heptylazodicarboxylate, triethylsilyl n-heptyl azodicarboxylate,triisopropylsilyl n-heptyl azodicarboxylate, tri-n-propylsilyl n-heptylazodicarboxylate, triisobutylsilyl n-heptyl azodicarboxylate,tri-t-butylsilyl n-heptyl azodicarboxylate, triphenylsilyl n-heptylazodicarboxylate, trimethylsilyl n-octyl azodicarboxylate, triethylsilyln-octyl azodicarboxylate, triisopropylsilyl n-octyl azodicarboxylate,tri-n-propylsilyl n-octyl azodicarboxylate, triisobutylsilyl n-octylazodicarboxylate, tri-t-butylsilyl n-octyl azodicarboxylate,triphenylsilyl n-octyl azodicarboxylate, trimethylsilyl cyclopentylazodicarboxylate, triethylsilyl cyclopentyl azodicarboxylate,triisopropylsilyl cyclopentyl azodicarboxylate, tri-n-propylsilylcyclopentyl azodicarboxylate, triisobutylsilyl cyclopentylazodicarboxylate, tri-t-butylsilyl cyclopentyl azodicarboxylate,triphenylsilyl cyclopentyl azodicarboxylate, trimethylsilyl cyclohexylazodicarboxylate, triethylsilyl cyclohexyl azodicarboxylate,triisopropylsilyl cyclohexyl azodicarboxylate, tri-n-propylsilylcyclohexyl azodicarboxylate, triisobutylsilyl cyclohexylazodicarboxylate, tri-t-butylsilyl cyclohexyl azodicarboxylate,triphenylsilyl cyclohexyl azodicarboxylate, trimethylsilyl benzylazodicarboxylate, triethylsilyl benzyl azodicarboxylate,triisopropylsilyl benzyl azodicarboxylate, tri-n-propylsilyl benzylazodicarboxylate, triisobutylsilyl benzyl azodicarboxylate,tri-t-butylsilyl benzyl azodicarboxylate, triphenylsilyl benzylazodicarboxylate, trimethylsilyl phenyl azodicarboxylate, triethylsilylphenyl azodicarboxylate, triisopropylsilyl phenyl azodicarboxylate,tri-n-propylsilyl phenyl azodicarboxylate, triisobutylsilyl phenylazodicarboxylate, tri-t-butylsilyl phenyl azodicarboxylate,triphenylsilyl phenyl azodicarboxylate, trimethylsilyl o-tolylazodicarboxylate, triethylsilyl o-tolyl azodicarboxylate,triisopropylsilyl o-tolyl azodicarboxylate, tri-n-propylsilyl o-tolylazodicarboxylate, triisobutylsilyl o-tolyl azodicarboxylate,tri-t-butylsilyl o-tolyl azodicarboxylate, triphenylsilyl o-tolylazodicarboxylate, trimethylsilyl m-tolyl azodicarboxylate, triethylsilylm-tolyl azodicarboxylate, triisopropylsilyl m-tolyl azodicarboxylate,tri-n-propylsilyl m-tolyl azodicarboxylate, triisobutylsilyl m-tolylazodicarboxylate, tri-t-butylsilyl m-tolyl azodicarboxylate,triphenylsilyl m-tolyl azodicarboxylate, trimethylsilyl p-tolylazodicarboxylate, triethylsilyl p-tolyl azodicarboxylate,triisopropylsilyl p-tolyl azodicarboxylate, tri-n-propylsilyl p-tolylazodicarboxylate, triisobutylsilyl p-tolyl azodicarboxylate,tri-t-butylsilyl p-tolyl azodicarboxylate, triphenylsilyl p-tolylazodicarboxylate, trimethylsilyl 2-ethylhexyl azodicarboxylate,triethylsilyl 2-ethylhexyl azodicarboxylate, triisopropylsilyl2-ethylhexyl azodicarboxylate, tri-n-propylsilyl 2-ethylhexylazodicarboxylate, triisobutylsilyl 2-ethylhexyl azodicarboxylate,tri-t-butylsilyl 2-ethylhexyl azodicarboxylate, and triphenylsilyl2-ethylhexyl azodicarboxylate.

Specific examples of dihydrocarbylhydrosilyl hydrocarbylazodicarboxylates include dimethylhydrosilyl methyl azodicarboxylate,diethylhydrosilyl methyl azodicarboxylate, diisopropylhydrosilyl methylazodicarboxylate, di-n-propylhydrosilyl methyl azodicarboxylate,di-t-butylhydrosilyl methyl azodicarboxylate, diphenylhydrosilyl methylazodicarboxylate, dimethylhydrosilyl ethyl azodicarboxylate,diethylhydrosilyl ethyl azodicarboxylate, diisopropylhydrosilyl ethylazodicarboxylate, di-n-propylhydrosilyl ethyl azodicarboxylate,di-t-butylhydrosilyl ethyl azodicarboxylate, diphenylhydrosilyl ethylazodicarboxylate, dimethylhydrosilyl n-propyl azodicarboxylate,diethylhydrosilyl n-propyl azodicarboxylate, diisopropylhydrosilyln-propyl azodicarboxylate, di-n-propylhydrosilyl n-propylazodicarboxylate, di-t-butylhydrosilyl n-propyl azodicarboxylate,diphenylhydrosilyl n-propyl azodicarboxylate, dimethylhydrosilylisopropyl azodicarboxylate, diethylhydrosilyl isopropylazodicarboxylate, diisopropylhydrosilyl isopropyl azodicarboxylate,di-n-propylhydrosilyl isopropyl azodicarboxylate, di-t-butylhydrosilylisopropyl azodicarboxylate, diphenylhydrosilyl isopropylazodicarboxylate, dimethylhydrosilyl n-butyl azodicarboxylate,diethylhydrosilyl n-butyl azodicarboxylate, diisopropylhydrosilyln-butyl azodicarboxylate, di-n-propylhydrosilyl n-butylazodicarboxylate, di-t-butylhydrosilyl n-butyl azodicarboxylate,diphenylhydrosilyl n-butyl azodicarboxylate, dimethylhydrosilyl isobutylazodicarboxylate, diethylhydrosilyl isobutyl azodicarboxylate,diisopropylhydrosilyl isobutyl azodicarboxylate, di-n-propylhydrosilylisobutyl azodicarboxylate, di-t-butylhydrosilyl isobutylazodicarboxylate, diphenylhydrosilyl isobutyl azodicarboxylate,dimethylhydrosilyl t-butyl azodicarboxylate, diethylhydrosilyl t-butylazodicarboxylate, diisopropylhydrosilyl t-butyl azodicarboxylate,di-n-propylhydrosilyl t-butyl azodicarboxylate, di-t-butylhydrosilylt-butyl azodicarboxylate, diphenylhydrosilyl t-butyl azodicarboxylate,dimethylhydrosilyl n-pentyl azodicarboxylate, diethylhydrosilyl n-pentylazodicarboxylate, diisopropylhydrosilyl n-pentyl azodicarboxylate,di-n-propylhydrosilyl n-pentyl azodicarboxylate, di-t-butylhydrosilyln-pentyl azodicarboxylate, diphenylhydrosilyl n-pentyl azodicarboxylate,dimethylhydrosilyl n-hexyl azodicarboxylate, diethylhydrosilyl n-hexylazodicarboxylate, diisopropylhydrosilyl n-hexyl azodicarboxylate,di-n-propylhydrosilyl n-hexyl azodicarboxylate, di-t-butylhydrosilyln-hexyl azodicarboxylate, diphenylhydrosilyl n-hexyl azodicarboxylate,dimethylhydrosilyl n-heptyl azodicarboxylate, diethylhydrosilyl n-heptylazodicarboxylate, diisopropylhydrosilyl n-heptyl azodicarboxylate,di-n-propylhydrosilyl n-heptyl azodicarboxylate, di-t-butylhydrosilyln-heptyl azodicarboxylate, diphenylhydrosilyl n-heptyl azodicarboxylate,dimethylhydrosilyl n-octyl azodicarboxylate, diethylhydrosilyl n-octylazodicarboxylate, diisopropylhydrosilyl n-octyl azodicarboxylate,di-n-propylhydrosilyl n-octyl azodicarboxylate, di-t-butylhydrosilyln-octyl azodicarboxylate, diphenylhydrosilyl n-octyl azodicarboxylate,dimethylhydrosilyl cyclopentyl azodicarboxylate, diethylhydrosilylcyclopentyl azodicarboxylate, diisopropylhydrosilyl cyclopentylazodicarboxylate, di-n-propylhydrosilyl cyclopentyl azodicarboxylate,di-t-butylhydrosilyl cyclopentyl azodicarboxylate, diphenylhydrosilylcyclopentyl azodicarboxylate, dimethylhydrosilyl cyclohexylazodicarboxylate, diethylhydrosilyl cyclohexyl azodicarboxylate,diisopropylhydrosilyl cyclohexyl azodicarboxylate, di-n-propylhydrosilylcyclohexyl azodicarboxylate, di-t-butylhydrosilyl cyclohexylazodicarboxylate, diphenylhydrosilyl cyclohexyl azodicarboxylate,dimethylhydrosilyl benzyl azodicarboxylate, diethylhydrosilyl benzylazodicarboxylate, diisopropylhydrosilyl benzyl azodicarboxylate,di-n-propylhydrosilyl benzyl azodicarboxylate, di-t-butylhydrosilylbenzyl azodicarboxylate, diphenylhydrosilyl benzyl azodicarboxylate,dimethylhydrosilyl phenyl azodicarboxylate, diethylhydrosilyl phenylazodicarboxylate, diisopropylhydrosilyl phenyl azodicarboxylate,di-n-propylhydrosilyl phenyl azodicarboxylate, di-t-butylhydrosilylphenyl azodicarboxylate, diphenylhydrosilyl phenyl azodicarboxylate,dimethylhydrosilyl o-tolyl azodicarboxylate, diethylhydrosilyl o-tolylazodicarboxylate, diisopropylhydrosilyl o-tolyl azodicarboxylate,di-n-propylhydrosilyl o-tolyl azodicarboxylate, di-t-butylhydrosilylo-tolyl azodicarboxylate, diphenylhydrosilyl o-tolyl azodicarboxylate,dimethylhydrosilyl m-tolyl azodicarboxylate, diethylhydrosilyl m-tolylazodicarboxylate, diisopropylhydrosilyl m-tolyl azodicarboxylate,di-n-propylhydrosilyl m-tolyl azodicarboxylate, di-t-butylhydrosilylm-tolyl azodicarboxylate, diphenylhydrosilyl m-tolyl azodicarboxylate,dimethylhydrosilyl p-tolyl azodicarboxylate, diethylhydrosilyl p-tolylazodicarboxylate, diisopropylhydrosilyl p-tolyl azodicarboxylate,di-n-propylhydrosilyl p-tolyl azodicarboxylate, di-t-butylhydrosilylp-tolyl azodicarboxylate, diphenylhydrosilyl p-tolyl azodicarboxylate,dimethylhydrosilyl 2-ethylhexyl azodicarboxylate, diethylhydrosilyl2-ethylhexyl azodicarboxylate, diisopropylhydrosilyl 2-ethylhexylazodicarboxylate, di-n-propylhydrosilyl 2-ethylhexyl azodicarboxylate,di-t-butylhydrosilyl 2-ethylhexyl azodicarboxylate, anddiphenylhydrosilyl 2-ethylhexyl azodicarboxylate.

Specific examples of dihydrocarbyl azothiodicarboxylates includedimethyl azothiodicarboxylate, diethyl azothiodicarboxylate, di-n-propylazothiodicarboxylate, diisopropyl azothiodicarboxylate, di-n-butylazothiodicarboxylate, diisobutyl azothiodicarboxylate, di-t-butylazothiodicarboxylate, di-n-pentyl azothiodicarboxylate, di-n-hexylazothiodicarboxylate, di-n-heptyl azothiodicarboxylate, di-n-octylazothiodicarboxylate, dicyclopentyl azothiodicarboxylate, dicyclohexylazothiodicarboxylate, dibenzyl azothiodicarboxylate, diphenylazothiodicarboxylate, di-o-tolyl azothiodicarboxylate, di-m-tolylazothiodicarboxylate, di-p-tolyl azothiodicarboxylate,bis(2-ethylhexyl)azothiodicarboxylate, methyl ethylazothiodicarboxylate, methyl n-propyl azothiodicarboxylate, ethyln-propyl azothiodicarboxylate, methyl isopropyl azothiodicarboxylate,ethyl isopropyl azothiodicarboxylate, n-propyl isopropylazothiodicarboxylate, methyl n-butyl azothiodicarboxylate, ethyl n-butylazothiodicarboxylate, n-propyl n-butyl azothiodicarboxylate, isopropyln-butyl azothiodicarboxylate, methyl isobutyl azothiodicarboxylate,ethyl isobutyl azothiodicarboxylate, n-propyl isobutylazothiodicarboxylate, isopropyl isobutyl azothiodicarboxylate, n-butylisobutyl azothiodicarboxylate, methyl t-butyl azothiodicarboxylate,ethyl t-butyl azothiodicarboxylate, n-propyl t-butylazothiodicarboxylate, isopropyl t-butyl azothiodicarboxylate, n-butylt-butyl azothiodicarboxylate, isobutyl t-butyl azothiodicarboxylate,methyl n-pentyl azothiodicarboxylate, ethyl n-pentylazothiodicarboxylate, n-propyl n-pentyl azothiodicarboxylate, isopropyln-pentyl azothiodicarboxylate, n-butyl n-pentyl azothiodicarboxylate,isobutyl n-pentyl azothiodicarboxylate, t-butyl n-pentylazothiodicarboxylate, methyl n-hexyl azothiodicarboxylate, ethyl n-hexylazothiodicarboxylate, n-propyl n-hexyl azothiodicarboxylate, isopropyln-hexyl azothiodicarboxylate, n-butyl n-hexyl azothiodicarboxylate,isobutyl n-hexyl azothiodicarboxylate, t-butyl n-hexylazothiodicarboxylate, n-pentyl n-hexyl azothiodicarboxylate, methyln-heptyl azothiodicarboxylate, ethyl n-heptyl azothiodicarboxylate,n-propyl n-heptyl azothiodicarboxylate, isopropyl n-heptylazothiodicarboxylate, n-butyl n-heptyl azothiodicarboxylate, isobutyln-heptyl azothiodicarboxylate, t-butyl n-heptyl azothiodicarboxylate,n-pentyl n-heptyl azothiodicarboxylate, n-hexyl n-heptylazothiodicarboxylate, methyl n-octyl azothiodicarboxylate, ethyl n-octylazothiodicarboxylate, n-propyl n-octyl azothiodicarboxylate, isopropyln-octyl azothiodicarboxylate, n-butyl n-octyl azothiodicarboxylate,isobutyl n-octyl azothiodicarboxylate, t-butyl n-octylazothiodicarboxylate, n-pentyl n-octyl azothiodicarboxylate, n-hexyln-octyl azothiodicarboxylate, n-heptyl n-octyl azothiodicarboxylate,methyl cyclopentyl azothiodicarboxylate, ethyl cyclopentylazothiodicarboxylate, n-propyl cyclopentyl azothiodicarboxylate,isopropyl cyclopentyl azothiodicarboxylate, n-butyl cyclopentylazothiodicarboxylate, isobutyl cyclopentyl azothiodicarboxylate, t-butylcyclopentyl azothiodicarboxylate, n-pentyl cyclopentylazothiodicarboxylate, n-hexyl cyclopentyl azothiodicarboxylate, n-heptylcyclopentyl azothiodicarboxylate, n-octyl cyclopentylazothiodicarboxylate, methyl cyclohexyl azothiodicarboxylate, ethylcyclohexyl azothiodicarboxylate, n-propyl cyclohexylazothiodicarboxylate, isopropyl cyclohexyl azothiodicarboxylate, n-butylcyclohexyl azothiodicarboxylate, isobutyl cyclohexylazothiodicarboxylate, t-butyl cyclohexyl azothiodicarboxylate, n-pentylcyclohexyl azothiodicarboxylate, n-hexyl cyclohexylazothiodicarboxylate, n-heptyl cyclohexyl azothiodicarboxylate, n-octylcyclohexyl azothiodicarboxylate, cyclopentyl cyclohexylazothiodicarboxylate, methyl benzyl azothiodicarboxylate, ethyl benzylazothiodicarboxylate, n-propyl benzyl azothiodicarboxylate, isopropylbenzyl azothiodicarboxylate, n-butyl benzyl azothiodicarboxylate,isobutyl benzyl azothiodicarboxylate, t-butyl benzylazothiodicarboxylate, n-pentyl benzyl azothiodicarboxylate, n-hexylbenzyl azothiodicarboxylate, n-heptyl benzyl azothiodicarboxylate,n-octyl benzyl azothiodicarboxylate, cyclopentyl benzylazothiodicarboxylate, cyclohexyl benzyl azothiodicarboxylate, methylphenyl azothiodicarboxylate, ethyl phenyl azothiodicarboxylate, n-propylphenyl azothiodicarboxylate, isopropyl phenyl azothiodicarboxylate,n-butyl phenyl azothiodicarboxylate, isobutyl phenylazothiodicarboxylate, t-butyl phenyl azothiodicarboxylate, n-pentylphenyl azothiodicarboxylate, n-hexyl phenyl azothiodicarboxylate,n-heptyl phenyl azothiodicarboxylate, n-octyl phenylazothiodicarboxylate, cyclopentyl phenyl azothiodicarboxylate,cyclohexyl phenyl azothiodicarboxylate, benzyl phenylazothiodicarboxylate, methyl o-tolyl azothiodicarboxylate, ethyl o-tolylazothiodicarboxylate, n-propyl o-tolyl azothiodicarboxylate, isopropylo-tolyl azothiodicarboxylate, n-butyl o-tolyl azothiodicarboxylate,isobutyl o-tolyl azothiodicarboxylate, t-butyl o-tolylazothiodicarboxylate, n-pentyl o-tolyl azothiodicarboxylate, n-hexylo-tolyl azothiodicarboxylate, n-heptyl o-tolyl azothiodicarboxylate,n-octyl o-tolyl azothiodicarboxylate, cyclopentyl o-tolylazothiodicarboxylate, cyclohexyl o-tolyl azothiodicarboxylate, benzylo-tolyl azothiodicarboxylate, phenyl o-tolyl azothiodicarboxylate,methyl m-tolyl azothiodicarboxylate, ethyl m-tolyl azothiodicarboxylate,n-propyl m-tolyl azothiodicarboxylate, isopropyl m-tolylazothiodicarboxylate, n-butyl m-tolyl azothiodicarboxylate, isobutylm-tolyl azothiodicarboxylate, t-butyl m-tolyl azothiodicarboxylate,n-pentyl m-tolyl azothiodicarboxylate, n-hexyl m-tolylazothiodicarboxylate, n-heptyl m-tolyl azothiodicarboxylate, n-octylm-tolyl azothiodicarboxylate, cyclopentyl m-tolyl azothiodicarboxylate,cyclohexyl m-tolyl azothiodicarboxylate, benzyl m-tolylazothiodicarboxylate, phenyl m-tolyl azothiodicarboxylate, o-tolylm-tolyl azothiodicarboxylate, methyl p-tolyl azothiodicarboxylate, ethylp-tolyl azothiodicarboxylate, n-propyl p-tolyl azothiodicarboxylate,isopropyl p-tolyl azothiodicarboxylate, n-butyl p-tolylazothiodicarboxylate, isobutyl p-tolyl azothiodicarboxylate, t-butylp-tolyl azothiodicarboxylate, n-pentyl p-tolyl azothiodicarboxylate,n-hexyl p-tolyl azothiodicarboxylate, n-heptyl p-tolylazothiodicarboxylate, n-octyl p-tolyl azothiodicarboxylate, cyclopentylp-tolyl azothiodicarboxylate, cyclohexyl p-tolyl azothiodicarboxylate,benzyl p-tolyl azothiodicarboxylate, phenyl p-tolylazothiodicarboxylate, o-tolyl p-tolyl azothiodicarboxylate, m-tolylp-tolyl azothiodicarboxylate, methyl 2-ethylhexyl azothiodicarboxylate,ethyl 2-ethylhexyl azothiodicarboxylate, n-propyl 2-ethylhexylazothiodicarboxylate, isopropyl 2-ethylhexyl azothiodicarboxylate,n-butyl 2-ethylhexyl azothiodicarboxylate, isobutyl 2-ethylhexylazothiodicarboxylate, t-butyl 2-ethylhexyl azothiodicarboxylate,n-pentyl 2-ethylhexyl azothiodicarboxylate, n-hexyl 2-ethylhexylazothiodicarboxylate, n-heptyl 2-ethylhexyl azothiodicarboxylate,n-octyl 2-ethylhexyl azothiodicarboxylate, cyclopentyl 2-ethylhexylazothiodicarboxylate, cyclohexyl 2-ethylhexyl azothiodicarboxylate,benzyl 2-ethylhexyl azothiodicarboxylate, phenyl 2-ethylhexylazothiodicarboxylate, o-tolyl 2-ethylhexyl azothiodicarboxylate, m-tolyl2-ethylhexyl azothiodicarboxylate, and p-tolyl 2-ethylhexylazothiodicarboxylate.

Specific examples of bis(trihydrocarbylsilyl)azothiodicarboxylatesinclude bis(trimethylsilyl)azothiodicarboxylate,bis(triethylsilyl)azothiodicarboxylate,bis(triisopropylsilyl)azothiodicarboxylate,bis(tri-n-propylsilyl)azothiodicarboxylate,bis(triisobutylsilyl)azothiodicarboxylate,bis(tri-t-butylsilyl)azothiodicarboxylate,bis(triphenylsilyl)azothiodicarboxylate, trimethylsilyl triethylsilylazothiodicarboxylate, trimethylsilyl triisopropylsilylazothiodicarboxylate, triethylsilyl triisopropylsilylazothiodicarboxylate, trimethylsilyl tri-n-propylsilylazothiodicarboxylate, triethylsilyl tri-n-propylsilylazothiodicarboxylate, triisopropylsilyl tri-n-propylsilylazothiodicarboxylate, trimethylsilyl triisobutylsilylazothiodicarboxylate, triethylsilyl triisobutylsilylazothiodicarboxylate, triisopropylsilyl triisobutylsilylazothiodicarboxylate, tri-n-propylsilyl triisobutylsilylazothiodicarboxylate, trimethylsilyl tri-t-butylsilylazothiodicarboxylate, triethylsilyl tri-t-butylsilylazothiodicarboxylate, triisopropylsilyl tri-t-butylsilylazothiodicarboxylate, tri-n-propylsilyl tri-t-butylsilylazothiodicarboxylate, triisobutylsilyl tri-t-butylsilylazothiodicarboxylate, trimethylsilyl triphenylsilylazothiodicarboxylate, triethylsilyl triphenylsilyl azothiodicarboxylate,triisopropylsilyl triphenylsilyl azothiodicarboxylate, tri-n-propylsilyltriphenylsilyl azothiodicarboxylate, triisobutylsilyl triphenylsilylazothiodicarboxylate, and tri-t-butylsilyl triphenylsilylazothiodicarboxylate.

Specific examples of bis(dihydrocarbylhydrosilyl)azothiodicarboxylatesinclude bis(dimethylhydrosilyl)azothiodicarboxylate,bis(diethylhydrosilyl)azothiodicarboxylate,bis(diisopropylhydrosilyl)azothiodicarboxylate,bis(di-n-propylhydrosilyl)azothiodicarboxylate,bis(di-t-butylhydrosilyl)azothiodicarboxylate,bis(diphenylhydrosilyl)azothiodicarboxylate, dimethylhydrosilyldiethylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldiisopropylhydrosilyl azothiodicarboxylate, diethylhydrosilyldiisopropylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldi-n-propylhydrosilyl azothiodicarboxylate, diethylhydrosilyldi-n-propylhydrosilyl azothiodicarboxylate, diisopropylhydrosilyldi-n-propylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, diethylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, diisopropylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, di-n-propylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, diethylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, diisopropylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, di-n-propylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, and di-t-butylhydrosilyldiphenylhydrosilyl azothiodicarboxylate.

Specific examples of trihydrocarbylsilyl hydrocarbylazothiodicarboxylates include trimethylsilyl methylazothiodicarboxylate, triethylsilyl methyl azothiodicarboxylate,triisopropylsilyl methyl azothiodicarboxylate, tri-n-propylsilyl methylazothiodicarboxylate, triisobutylsilyl methyl azothiodicarboxylate,tri-t-butylsilyl methyl azothiodicarboxylate, triphenylsilyl methylazothiodicarboxylate, trimethylsilyl ethyl azothiodicarboxylate,triethylsilyl ethyl azothiodicarboxylate, triisopropylsilyl ethylazothiodicarboxylate, tri-n-propylsilyl ethyl azothiodicarboxylate,triisobutylsilyl ethyl azothiodicarboxylate, tri-t-butylsilyl ethylazothiodicarboxylate, triphenylsilyl ethyl azothiodicarboxylate,trimethylsilyl n-propyl azothiodicarboxylate, triethylsilyl n-propylazothiodicarboxylate, triisopropylsilyl n-propyl azothiodicarboxylate,tri-n-propylsilyl n-propyl azothiodicarboxylate, triisobutylsilyln-propyl azothiodicarboxylate, tri-t-butylsilyl n-propylazothiodicarboxylate, triphenylsilyl n-propyl azothiodicarboxylate,trimethylsilyl isopropyl azothiodicarboxylate, triethylsilyl isopropylazothiodicarboxylate, triisopropylsilyl isopropyl azothiodicarboxylate,tri-n-propylsilyl isopropyl azothiodicarboxylate, triisobutylsilylisopropyl azothiodicarboxylate, tri-t-butylsilyl isopropylazothiodicarboxylate, triphenylsilyl isopropyl azothiodicarboxylate,trimethylsilyl n-butyl azothiodicarboxylate, triethylsilyl n-butylazothiodicarboxylate, triisopropylsilyl n-butyl azothiodicarboxylate,tri-n-propylsilyl n-butyl azothiodicarboxylate, triisobutylsilyl n-butylazothiodicarboxylate, tri-t-butylsilyl n-butyl azothiodicarboxylate,triphenylsilyl n-butyl azothiodicarboxylate, trimethylsilyl isobutylazothiodicarboxylate, triethylsilyl isobutyl azothiodicarboxylate,triisopropylsilyl isobutyl azothiodicarboxylate, tri-n-propylsilylisobutyl azothiodicarboxylate, triisobutylsilyl isobutylazothiodicarboxylate, tri-t-butylsilyl isobutyl azothiodicarboxylate,triphenylsilyl isobutyl azothiodicarboxylate, trimethylsilyl t-butylazothiodicarboxylate, triethylsilyl t-butyl azothiodicarboxylate,triisopropylsilyl t-butyl azothiodicarboxylate, tri-n-propylsilylt-butyl azothiodicarboxylate, triisobutylsilyl t-butylazothiodicarboxylate, tri-t-butylsilyl t-butyl azothiodicarboxylate,triphenylsilyl t-butyl azothiodicarboxylate, trimethylsilyl n-pentylazothiodicarboxylate, triethylsilyl n-pentyl azothiodicarboxylate,triisopropylsilyl n-pentyl azothiodicarboxylate, tri-n-propylsilyln-pentyl azothiodicarboxylate, triisobutylsilyl n-pentylazothiodicarboxylate, tri-t-butylsilyl n-pentyl azothiodicarboxylate,triphenylsilyl n-pentyl azothiodicarboxylate, trimethylsilyl n-hexylazothiodicarboxylate, triethylsilyl n-hexyl azothiodicarboxylate,triisopropylsilyl n-hexyl azothiodicarboxylate, tri-n-propylsilyln-hexyl azothiodicarboxylate, triisobutylsilyl n-hexylazothiodicarboxylate, tri-t-butylsilyl n-hexyl azothiodicarboxylate,triphenylsilyl n-hexyl azothiodicarboxylate, trimethylsilyl n-heptylazothiodicarboxylate, triethylsilyl n-heptyl azothiodicarboxylate,triisopropylsilyl n-heptyl azothiodicarboxylate, tri-n-propylsilyln-heptyl azothiodicarboxylate, triisobutylsilyl n-heptylazothiodicarboxylate, tri-t-butylsilyl n-heptyl azothiodicarboxylate,triphenylsilyl n-heptyl azothiodicarboxylate, trimethylsilyl n-octylazothiodicarboxylate, triethylsilyl n-octyl azothiodicarboxylate,triisopropylsilyl n-octyl azothiodicarboxylate, tri-n-propylsilyln-octyl azothiodicarboxylate, triisobutylsilyl n-octylazothiodicarboxylate, tri-t-butylsilyl n-octyl azothiodicarboxylate,triphenylsilyl n-octyl azothiodicarboxylate, trimethylsilyl cyclopentylazothiodicarboxylate, triethylsilyl cyclopentyl azothiodicarboxylate,triisopropylsilyl cyclopentyl azothiodicarboxylate, tri-n-propylsilylcyclopentyl azothiodicarboxylate, triisobutylsilyl cyclopentylazothiodicarboxylate, tri-t-butylsilyl cyclopentyl azothiodicarboxylate,triphenylsilyl cyclopentyl azothiodicarboxylate, trimethylsilylcyclohexyl azothiodicarboxylate, triethylsilyl cyclohexylazothiodicarboxylate, triisopropylsilyl cyclohexyl azothiodicarboxylate,tri-n-propylsilyl cyclohexyl azothiodicarboxylate, triisobutylsilylcyclohexyl azothiodicarboxylate, tri-t-butylsilyl cyclohexylazothiodicarboxylate, triphenylsilyl cyclohexyl azothiodicarboxylate,trimethylsilyl benzyl azothiodicarboxylate, triethylsilyl benzylazothiodicarboxylate, triisopropylsilyl benzyl azothiodicarboxylate,tri-n-propylsilyl benzyl azothiodicarboxylate, triisobutylsilyl benzylazothiodicarboxylate, tri-t-butylsilyl benzyl azothiodicarboxylate,triphenylsilyl benzyl azothiodicarboxylate, trimethylsilyl phenylazothiodicarboxylate, triethylsilyl phenyl azothiodicarboxylate,triisopropylsilyl phenyl azothiodicarboxylate, tri-n-propylsilyl phenylazothiodicarboxylate, triisobutylsilyl phenyl azothiodicarboxylate,tri-t-butylsilyl phenyl azothiodicarboxylate, triphenylsilyl phenylazothiodicarboxylate, trimethylsilyl o-tolyl azothiodicarboxylate,triethylsilyl o-tolyl azothiodicarboxylate, triisopropylsilyl o-tolylazothiodicarboxylate, tri-n-propylsilyl o-tolyl azothiodicarboxylate,triisobutylsilyl o-tolyl azothiodicarboxylate, tri-t-butylsilyl o-tolylazothiodicarboxylate, triphenylsilyl o-tolyl azothiodicarboxylate,trimethylsilyl m-tolyl azothiodicarboxylate, triethylsilyl m-tolylazothiodicarboxylate, triisopropylsilyl m-tolyl azothiodicarboxylate,tri-n-propylsilyl m-tolyl azothiodicarboxylate, triisobutylsilyl m-tolylazothiodicarboxylate, tri-t-butylsilyl m-tolyl azothiodicarboxylate,triphenylsilyl m-tolyl azothiodicarboxylate, trimethylsilyl p-tolylazothiodicarboxylate, triethylsilyl p-tolyl azothiodicarboxylate,triisopropylsilyl p-tolyl azothiodicarboxylate, tri-n-propylsilylp-tolyl azothiodicarboxylate, triisobutylsilyl p-tolylazothiodicarboxylate, tri-t-butylsilyl p-tolyl azothiodicarboxylate,triphenylsilyl p-tolyl azothiodicarboxylate, trimethylsilyl 2-ethylhexylazothiodicarboxylate, triethylsilyl 2-ethylhexyl azothiodicarboxylate,triisopropylsilyl 2-ethylhexyl azothiodicarboxylate, tri-n-propylsilyl2-ethylhexyl azothiodicarboxylate, triisobutylsilyl 2-ethylhexylazothiodicarboxylate, tri-t-butylsilyl 2-ethylhexylazothiodicarboxylate, and triphenylsilyl 2-ethylhexylazothiodicarboxylate.

Specific examples of dihydrocarbylhydrosilyl hydrocarbylazothiodicarboxylates include dimethylhydrosilyl methylazothiodicarboxylate, diethylhydrosilyl methyl azothiodicarboxylate,diisopropylhydrosilyl methyl azothiodicarboxylate, di-n-propylhydrosilylmethyl azothiodicarboxylate, di-t-butylhydrosilyl methylazothiodicarboxylate, diphenylhydrosilyl methyl azothiodicarboxylate,dimethylhydrosilyl ethyl azothiodicarboxylate, diethylhydrosilyl ethylazothiodicarboxylate, diisopropylhydrosilyl ethyl azothiodicarboxylate,di-n-propylhydrosilyl ethyl azothiodicarboxylate, di-t-butylhydrosilylethyl azothiodicarboxylate, diphenylhydrosilyl ethylazothiodicarboxylate, dimethylhydrosilyl n-propyl azothiodicarboxylate,diethylhydrosilyl n-propyl azothiodicarboxylate, diisopropylhydrosilyln-propyl azothiodicarboxylate, di-n-propylhydrosilyl n-propylazothiodicarboxylate, di-t-butylhydrosilyl n-propylazothiodicarboxylate, diphenylhydrosilyl n-propyl azothiodicarboxylate,dimethylhydrosilyl isopropyl azothiodicarboxylate, diethylhydrosilylisopropyl azothiodicarboxylate, diisopropylhydrosilyl isopropylazothiodicarboxylate, di-n-propylhydrosilyl isopropylazothiodicarboxylate, di-t-butylhydrosilyl isopropylazothiodicarboxylate, diphenylhydrosilyl isopropyl azothiodicarboxylate,dimethylhydrosilyl n-butyl azothiodicarboxylate, diethylhydrosilyln-butyl azothiodicarboxylate, diisopropylhydrosilyl n-butylazothiodicarboxylate, di-n-propylhydrosilyl n-butylazothiodicarboxylate, di-t-butylhydrosilyl n-butyl azothiodicarboxylate,diphenylhydrosilyl n-butyl azothiodicarboxylate, dimethylhydrosilylisobutyl azothiodicarboxylate, diethylhydrosilyl isobutylazothiodicarboxylate, diisopropylhydrosilyl isobutylazothiodicarboxylate, di-n-propylhydrosilyl isobutylazothiodicarboxylate, di-t-butylhydrosilyl isobutylazothiodicarboxylate, diphenylhydrosilyl isobutyl azothiodicarboxylate,dimethylhydrosilyl t-butyl azothiodicarboxylate, diethylhydrosilylt-butyl azothiodicarboxylate, diisopropylhydrosilyl t-butylazothiodicarboxylate, di-n-propylhydrosilyl t-butylazothiodicarboxylate, di-t-butylhydrosilyl t-butyl azothiodicarboxylate,diphenylhydrosilyl t-butyl azothiodicarboxylate, dimethylhydrosilyln-pentyl azothiodicarboxylate, diethylhydrosilyl n-pentylazothiodicarboxylate, diisopropylhydrosilyl n-pentylazothiodicarboxylate, di-n-propylhydrosilyl n-pentylazothiodicarboxylate, di-t-butylhydrosilyl n-pentylazothiodicarboxylate, diphenylhydrosilyl n-pentyl azothiodicarboxylate,dimethylhydrosilyl n-hexyl azothiodicarboxylate, diethylhydrosilyln-hexyl azothiodicarboxylate, diisopropylhydrosilyl n-hexylazothiodicarboxylate, di-n-propylhydrosilyl n-hexylazothiodicarboxylate, di-t-butylhydrosilyl n-hexyl azothiodicarboxylate,diphenylhydrosilyl n-hexyl azothiodicarboxylate, dimethylhydrosilyln-heptyl azothiodicarboxylate, diethylhydrosilyl n-heptylazothiodicarboxylate, diisopropylhydrosilyl n-heptylazothiodicarboxylate, di-n-propylhydrosilyl n-heptylazothiodicarboxylate, di-t-butylhydrosilyl n-heptylazothiodicarboxylate, diphenylhydrosilyl n-heptyl azothiodicarboxylate,dimethylhydrosilyl n-octyl azothiodicarboxylate, diethylhydrosilyln-octyl azothiodicarboxylate, diisopropylhydrosilyl n-octylazothiodicarboxylate, di-n-propylhydrosilyl n-octylazothiodicarboxylate, di-t-butylhydrosilyl n-octyl azothiodicarboxylate,diphenylhydrosilyl n-octyl azothiodicarboxylate, dimethylhydrosilylcyclopentyl azothiodicarboxylate, diethylhydrosilyl cyclopentylazothiodicarboxylate, diisopropylhydrosilyl cyclopentylazothiodicarboxylate, di-n-propylhydrosilyl cyclopentylazothiodicarboxylate, di-t-butylhydrosilyl cyclopentylazothiodicarboxylate, diphenylhydrosilyl cyclopentylazothiodicarboxylate, dimethylhydrosilyl cyclohexylazothiodicarboxylate, diethylhydrosilyl cyclohexyl azothiodicarboxylate,diisopropylhydrosilyl cyclohexyl azothiodicarboxylate,di-n-propylhydrosilyl cyclohexyl azothiodicarboxylate,di-t-butylhydrosilyl cyclohexyl azothiodicarboxylate, diphenylhydrosilylcyclohexyl azothiodicarboxylate, dimethylhydrosilyl benzylazothiodicarboxylate, diethylhydrosilyl benzyl azothiodicarboxylate,diisopropylhydrosilyl benzyl azothiodicarboxylate, di-n-propylhydrosilylbenzyl azothiodicarboxylate, di-t-butylhydrosilyl benzylazothiodicarboxylate, diphenylhydrosilyl benzyl azothiodicarboxylate,dimethylhydrosilyl phenyl azothiodicarboxylate, diethylhydrosilyl phenylazothiodicarboxylate, diisopropylhydrosilyl phenyl azothiodicarboxylate,di-n-propylhydrosilyl phenyl azothiodicarboxylate, di-t-butylhydrosilylphenyl azothiodicarboxylate, diphenylhydrosilyl phenylazothiodicarboxylate, dimethylhydrosilyl o-tolyl azothiodicarboxylate,diethylhydrosilyl o-tolyl azothiodicarboxylate, diisopropylhydrosilylo-tolyl azothiodicarboxylate, di-n-propylhydrosilyl o-tolylazothiodicarboxylate, di-t-butylhydrosilyl o-tolyl azothiodicarboxylate,diphenylhydrosilyl o-tolyl azothiodicarboxylate, dimethylhydrosilylm-tolyl azothiodicarboxylate, diethylhydrosilyl m-tolylazothiodicarboxylate, diisopropylhydrosilyl m-tolylazothiodicarboxylate, di-n-propylhydrosilyl m-tolylazothiodicarboxylate, di-t-butylhydrosilyl m-tolyl azothiodicarboxylate,diphenylhydrosilyl m-tolyl azothiodicarboxylate, dimethylhydrosilylp-tolyl azothiodicarboxylate, diethylhydrosilyl p-tolylazothiodicarboxylate, diisopropylhydrosilyl p-tolylazothiodicarboxylate, di-n-propylhydrosilyl p-tolylazothiodicarboxylate, di-t-butylhydrosilyl p-tolyl azothiodicarboxylate,diphenylhydrosilyl p-tolyl azothiodicarboxylate, dimethylhydrosilyl2-ethylhexyl azothiodicarboxylate, diethylhydrosilyl 2-ethylhexylazothiodicarboxylate, diisopropylhydrosilyl 2-ethylhexylazothiodicarboxylate, di-n-propylhydrosilyl 2-ethylhexylazothiodicarboxylate, di-t-butylhydrosilyl 2-ethylhexylazothiodicarboxylate, and diphenylhydrosilyl 2-ethylhexylazothiodicarboxylate.

The amount of the azodiester that can be added to the polymerizationmixture to yield the functionalized polymer of this invention may dependon various factors including the type and amount of catalyst orinitiator used to synthesize the reactive polymer and the desired degreeof functionalization. In one or more embodiments, where the reactivepolymer is prepared by employing a lanthanide-based catalyst, the amountof the azodiester employed can be described with reference to thelanthanide metal of the lanthanide-containing compound. For example, themolar ratio of the azodiester to the lanthanide metal may be from about1:1 to about 200:1, in other embodiments from about 5:1 to about 150:1,and in other embodiments from about 10:1 to about 100:1.

In other embodiments, such as where the reactive polymer is prepared byusing an anionic initiator, the amount of the azodiester employed can bedescribed with reference to the amount of metal cation associated withthe initiator. For example, where an organolithium initiator isemployed, the molar ratio of the azodiester to the lithium cation may befrom about 0.3:1 to about 2:1, in other embodiments from about 0.6:1 toabout 1.5:1, and in other embodiments from 0.8:1 to about 1.2:1.

In one or more embodiments, in addition to the azodiester, aco-functionalizing agent may also be added to the polymerization mixtureto yield a functionalized polymer with tailored properties. A mixture oftwo or more co-functionalizing agents may also be employed. Theco-functionalizing agent may be added to the polymerization mixtureprior to, together with, or after the introduction of the azodiester. Inone or more embodiments, the co-functionalizing agent is added to thepolymerization mixture at least 5 minutes after, in other embodiments atleast 10 minutes after, and in other embodiments at least 30 minutesafter the introduction of the azodiester.

In one or more embodiments, co-functionalizing agents include compoundsor reagents that can react with a reactive polymer produced by thisinvention and thereby provide the polymer with a functional group thatis distinct from a propagating chain that has not been reacted with theco-functionalizing agent. The functional group may be reactive orinteractive with other polymer chains (propagating and/ornon-propagating) or with other constituents such as reinforcing fillers(e.g. carbon black) that may be combined with the polymer. In one ormore embodiments, the reaction between the co-functionalizing agent andthe reactive polymer proceeds via an addition or substitution reaction.

Useful co-functionalizing agents may include compounds that simplyprovide a functional group at the end of a polymer chain without joiningtwo or more polymer chains together, as well as compounds that cancouple or join two or more polymer chains together via a functionallinkage to form a single macromolecule. The latter type ofco-functionalizing agents may also be referred to as coupling agents.

In one or more embodiments, co-functionalizing agents include compoundsthat will add or impart a heteroatom to the polymer chain. In particularembodiments, co-functionalizing agents include those compounds that willimpart a functional group to the polymer chain to form a functionalizedpolymer that reduces the 50° C. hysteresis loss of a carbon-black filledvulcanizates prepared from the functionalized polymer as compared tosimilar carbon-black filled vulcanizates prepared fromnon-functionalized polymer. In one or more embodiments, this reductionin hysteresis loss is at least 5%, in other embodiments at least 10%,and in other embodiments at least 15%.

In one or more embodiments, suitable co-functionalizing agents includethose compounds that contain groups that may react with the reactivepolymers produced in accordance with this invention. Exemplaryco-functionalizing agents include ketones, quinones, aldehydes, amides,esters, isocyanates, isothiocyanates, epoxides, imines, aminoketones,aminothioketones, and acid anhydrides. Examples of these compounds aredisclosed in U.S. Pat. Nos. 4,906,706, 4,990,573, 5,064,910, 5,567,784,5,844,050, 6838,526, 6977,281, and 6,992,147; U.S. Pat. Publication Nos.2006/0004131 A1, 2006/0025539 A1, 2006/0030677 A1, and 2004/0147694 A1;Japanese Patent Application Nos. 05-051406A, 05-059103A, 10-306113A, and11-035633A; which are incorporated herein by reference. Other examplesof co-functionalizing agents include azine compounds as described inU.S. Pat. No. 7,879,952, hydrobenzamide compounds as disclosed in U.S.Pat. No. 7,671,138, nitro compounds as disclosed in U.S. Pat. No.7,732,534, and protected oxime compounds as disclosed in U.S. Pat. No.8,088,868, all of which are incorporated herein by reference.

In particular embodiments, the co-functionalizing agents employed may bemetal halides, metalloid halides, alkoxysilanes, metal carboxylates,hydrocarbylmetal carboxylates, hydrocarbylmetal ester-carboxylates, andmetal alkoxides.

Exemplary metal halide compounds include tin tetrachloride, tintetrabromide, tin tetraiodide, n-butyltin trichloride, phenyltintrichloride, di-n-butyltin dichloride, diphenyltin dichloride,tri-n-butyltin chloride, triphenyltin chloride, germanium tetrachloride,germanium tetrabromide, germanium tetraiodide, n-butylgermaniumtrichloride, di-n-butylgermanium dichloride, and tri-n-butylgermaniumchloride.

Exemplary metalloid halide compounds include silicon tetrachloride,silicon tetrabromide, silicon tetraiodide, methyltrichlorosilane,phenyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane,boron trichloride, boron tribromide, boron triiodide, phosphoroustrichloride, phosphorous tribromide, and phosphorus triiodide.

In one or more embodiments, the alkoxysilanes may include at least onegroup selected from the group consisting of an epoxy group and anisocyanate group.

Exemplary alkoxysilane compounds including an epoxy group include(3-glycidyloxypropyl)trimethoxysilane,(3-glycidyloxypropyl)triethoxysilane,(3-glycidyloxypropyl)triphenoxysilane,(3-glycidyloxypropyl)methyldimethoxysilane,(3-glycidyloxypropyl)methyldiethoxysilane,(3-glycidyloxypropyl)methyldiphenoxysilane,[2-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane, and[2-(3,4-epoxycyclohexyl)ethyl]triethoxysilane.

Exemplary alkoxysilane compounds including an isocyanate group include(3-isocyanatopropyl)trimethoxysilane,(3-isocyanatopropyl)triethoxysilane,(3-isocyanatopropyl)triphenoxysilane,(3-isocyanatopropyl)methyldimethoxysilane,(3-isocyanatopropyl)methyldiethoxysilane(3-isocyanatopropyl)methyldiphenoxysilane,and (isocyanatomethyl)methyldimethoxysilane.

Exemplary metal carboxylate compounds include tin tetraacetate, tinbis(2-ethylhexanaote), and tin bis(neodecanoate).

Exemplary hydrocarbylmetal carboxylate compounds include triphenyltin2-ethylhexanoate, tri-n-butyltin 2-ethylhexanoate, tri-n-butyltinneodecanoate, triisobutyltin 2-ethylhexanoate, diphenyltinbis(2-ethylhexanoate), di-n-butyltin bis(2-ethylhexanoate),di-n-butyltin bis(neodecanoate), phenyltin tris(2-ethylhexanoate), andn-butyltin tris(2-ethylhexanoate).

Exemplary hydrocarbylmetal ester-carboxylate compounds includedi-n-butyltin bis(n-octylmaleate), di-n-octyltin bis(n-octylmaleate),diphenyltin bis(n-octylmaleate), di-n-butyltin bis(2-ethylhexylmaleate),di-n-octyltin bis(2-ethylhexylmaleate), and diphenyltinbis(2-ethylhexylmaleate).

Exemplary metal alkoxide compounds include dimethoxytin, diethoxytin,tetraethoxytin, tetra-n-propoxytin, tetraisopropoxytin,tetra-n-butoxytin, tetraisobutoxytin, tetra-t-butoxytin, andtetraphenoxytin.

The amount of the co-functionalizing agent that can be added to thepolymerization mixture may depend on various factors including the typeand amount of catalyst or initiator used to synthesize the reactivepolymer and the desired degree of functionalization. In one or moreembodiments, where the reactive polymer is prepared by employing alanthanide-based catalyst, the amount of the co-functionalizing agentemployed can be described with reference to the lanthanide metal of thelanthanide-containing compound. For example, the molar ratio of theco-functionalizing agent to the lanthanide metal may be from about 1:1to about 200:1, in other embodiments from about 5:1 to about 150:1, andin other embodiments from about 10:1 to about 100:1.

In other embodiments, such as where the reactive polymer is prepared byusing an anionic initiator, the amount of the co-functionalizing agentemployed can be described with reference to the amount of metal cationassociated with the initiator. For example, where an organolithiuminitiator is employed, the molar ratio of the co-functionalizing agentto the lithium cation may be from about 0.3:1 to about 2:1, in otherembodiments from about 0.6:1 to about 1.5:1, and in other embodimentsfrom 0.8:1 to about 1.2:1.

The amount of the co-functionalizing agent employed can also bedescribed with reference to the azodiester. In one or more embodiments,the molar ratio of the co-functionalizing agent to the azodiester may befrom about 0.05:1 to about 1:1, in other embodiments from about 0.1:1 toabout 0.8:1, and in other embodiments from about 0.2:1 to about 0.6:1.

In one or more embodiments, the azodiester (and optionally theco-functionalizing agent) may be introduced to the polymerizationmixture at a location (e.g., within a vessel) where the polymerizationhas been conducted. In other embodiments, the azodiester may beintroduced to the polymerization mixture at a location that is distinctfrom where the polymerization has taken place. For example, theazodiester may be introduced to the polymerization mixture in downstreamvessels including downstream reactors or tanks, in-line reactors ormixers, extruders, or devolatilizers.

In one or more embodiments, the azodiester (and optionally theco-functionalizing agent) can be reacted with the reactive polymer aftera desired monomer conversion is achieved but before the polymerizationmixture is quenched by a quenching agent. In one or more embodiments,the reaction between the azodiester and the reactive polymer may takeplace within 30 minutes, in other embodiments within 5 minutes, and inother embodiments within one minute after the peak polymerizationtemperature is reached. In one or more embodiments, the reaction betweenthe azodiester and the reactive polymer can occur once the peakpolymerization temperature is reached. In other embodiments, thereaction between the azodiester and the reactive polymer can occur afterthe reactive polymer has been stored. In one or more embodiments, thestorage of the reactive polymer occurs at room temperature or below roomtemperature under an inert atmosphere. In one or more embodiments, thereaction between the azodiester and the reactive polymer may take placeat a temperature from about 10° C. to about 150° C., and in otherembodiments from about 20° C. to about 100° C. The time required forcompleting the reaction between the azodiester and the reactive polymerdepends on various factors such as the type and amount of the catalystor initiator used to prepare the reactive polymer, the type and amountof the azodiester, as well as the temperature at which thefunctionalization reaction is conducted. In one or more embodiments, thereaction between the azodiester and the reactive polymer can beconducted for about 10 to 60 minutes.

In one or more embodiments, after the reaction between the reactivepolymer and the azodiester (and optionally the co-functionalizing agent)has been accomplished or completed, a quenching agent can be added tothe polymerization mixture in order to protonate the reaction productbetween the reactive polymer and the azodiester, inactivate any residualreactive polymer chains, and/or inactivate the catalyst or catalystcomponents. The quenching agent may include a protic compound, whichincludes, but is not limited to, an alcohol, a carboxylic acid, aninorganic acid, water, or a mixture thereof. An antioxidant such as2,6-di-tert-butyl-4-methylphenol may be added along with, before, orafter the addition of the quenching agent. The amount of the antioxidantemployed may be in the range of 0.2% to 1% by weight of the polymerproduct. Additionally, the polymer product can be oil extended by addingan oil to the polymer, which may be in the form of a polymer cement orpolymer dissolved or suspended in monomer. Practice of the presentinvention does not limit the amount of oil that may be added, andtherefore conventional amounts may be added (e.g., 5-50 phr). Usefuloils or extenders that may be employed include, but are not limited to,aromatic oils, paraffinic oils, naphthenic oils, vegetable oils otherthan castor oils, low PCA oils including MES, TDAE, and SRAE, and heavynaphthenic oils.

Once the polymerization mixture has been quenched, the variousconstituents of the polymerization mixture may be recovered. In one ormore embodiments, the unreacted monomer can be recovered from thepolymerization mixture. For example, the monomer can be distilled fromthe polymerization mixture by using techniques known in the art. In oneor more embodiments, a devolatilizer may be employed to remove themonomer from the polymerization mixture. Once the monomer has beenremoved from the polymerization mixture, the monomer may be purified,stored, and/or recycled back to the polymerization process.

The polymer product may be recovered from the polymerization mixture byusing techniques known in the art. In one or more embodiments,desolventization and drying techniques may be used. For instance, thepolymer can be recovered by passing the polymerization mixture through aheated screw apparatus, such as a desolventizing extruder, in which thevolatile substances are removed by evaporation at appropriatetemperatures (e.g., about 100° C. to about 170° C.) and underatmospheric or sub-atmospheric pressure. This treatment serves to removeunreacted monomer as well as any low-boiling solvent. Alternatively, thepolymer can also be recovered by subjecting the polymerization mixtureto steam desolventization, followed by drying the resulting polymercrumbs in a hot air tunnel. The polymer can also be recovered bydirectly drying the polymerization mixture on a drum dryer.

The reactive polymer and the azodiester (and optionally theco-functionalizing agent) are believed to react to produce a novelfunctionalized polymer, wherein the residue of the azodiester isimparted to the end of the polymer chain. It is believed that thereactive end of the polymer chain reacts with the azodiester.Nonetheless, the exact chemical structure of the functionalized polymerproduced in every embodiment is not known with any great degree ofcertainty, particularly as the structure relates to the residue impartedto the polymer chain end by the azodiester and optionally theco-functionalizing agent. Indeed, it is speculated that the structure ofthe functionalized polymer may depend upon various factors such as theconditions employed to prepare the reactive polymer (e.g., the type andamount of the catalyst or initiator) and the conditions employed toreact the azodiester (and optionally the co-functionalizing agent) withthe reactive polymer (e.g., the types and amounts of the azodiester andthe co-functionalizing agent). The functionalized polymer resulting fromthe reaction between the reactive polymer and the azodiester can beprotonated or further modified.

In one or more embodiments, the functionalized polymers preparedaccording to this invention may contain unsaturation. In these or otherembodiments, the functionalized polymers are vulcanizable. In one ormore embodiments, the functionalized polymers can have a glasstransition temperature (T_(g)) that is less than 0° C., in otherembodiments less than −20° C., and in other embodiments less than −30°C. In one embodiment, these polymers may exhibit a single glasstransition temperature. In particular embodiments, the polymers may behydrogenated or partially hydrogenated.

In one or more embodiments, the functionalized polymers of thisinvention may be cis-1,4-polydienes having a cis-1,4-linkage contentthat is greater than 60%, in other embodiments greater than about 75%,in other embodiments greater than about 90%, and in other embodimentsgreater than about 95%, where the percentages are based upon the numberof diene mer units adopting the cis-1,4 linkage versus the total numberof diene mer units. Also, these polymers may have a 1,2-linkage contentthat is less than about 7%, in other embodiments less than 5%, in otherembodiments less than 2%, and in other embodiments less than 1%, wherethe percentages are based upon the number of diene mer units adoptingthe 1,2-linkage versus the total number of diene mer units. The balanceof the diene mer units may adopt the trans-1,4-linkage. The cis-1,4-,1,2-, and trans-1,4-linkage contents can be determined by infraredspectroscopy. The number average molecular weight (M_(n)) of thesepolymers may be from about 1,000 to about 1,000,000, in otherembodiments from about 5,000 to about 200,000, in other embodiments fromabout 25,000 to about 150,000, and in other embodiments from about50,000 to about 120,000, as determined by using gel permeationchromatography (GPC) calibrated with polystyrene standards andMark-Houwink constants for the polymer in question. The molecular weightdistribution or polydispersity (M_(w)/M_(n)) of these polymers may befrom about 1.5 to about 5.0, and in other embodiments from about 2.0 toabout 4.0.

In one or more embodiments, the functionalized polymers of thisinvention may be polydienes having medium or low cis-1,4-linkagecontents. These polymers, which can be prepared by anionicpolymerization techniques, can have a cis-1,4-linkage content of fromabout 10% to 60%, in other embodiments from about 15% to 55%, and inother embodiments from about 20% to about 50%. These polydienes may alsohave a 1,2-linkage content from about 10% to about 90%, in otherembodiments from about 10% to about 60%, in other embodiments from about15% to about 50%, and in other embodiments from about 20% to about 45%.In particular embodiments, where the polydienes are prepared byemploying a functional anionic initiator, the head of the polymer chainincludes a functional group that is the residue of the functionalinitiator.

In particular embodiments, the functionalized polymers of this inventionare copolymers of 1,3-butadiene, styrene, and optionally isoprene. Thesemay include random copolymers and block copolymers.

Advantageously, the functionalized polymers of this invention mayexhibit improved cold-flow resistance and provide rubber compositionsthat demonstrate reduced hysteresis. The functionalized polymers areparticularly useful in preparing rubber compositions that can be used tomanufacture tire components. Rubber compounding techniques and theadditives employed therein are generally disclosed in The Compoundingand Vulcanization of Rubber, in Rubber Technology (2^(nd) Ed. 1973).

The rubber compositions can be prepared by using the functionalizedpolymers alone or together with other elastomers (i.e., polymers thatcan be vulcanized to form compositions possessing rubbery or elastomericproperties). Other elastomers that may be used include natural andsynthetic rubbers. The synthetic rubbers typically derive from thepolymerization of conjugated diene monomer, the copolymerization ofconjugated diene monomer with other monomer such as vinyl-substitutedaromatic monomer, or the copolymerization of ethylene with one or moreα-olefins and optionally one or more diene monomers.

Exemplary elastomers include natural rubber, synthetic polyisoprene,polybutadiene, polyisobutylene-co-isoprene, neoprene,poly(ethylene-co-propylene), poly(styrene-co-butadiene),poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene),poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene),polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber,epichlorohydrin rubber, and mixtures thereof. These elastomers can havea myriad of macromolecular structures including linear, branched, andstar-shaped structures.

The rubber compositions may include fillers such as inorganic andorganic fillers. Examples of organic fillers include carbon black andstarch. Examples of inorganic fillers include silica, aluminumhydroxide, magnesium hydroxide, mica, talc (hydrated magnesiumsilicate), and clays (hydrated aluminum silicates). Carbon blacks andsilicas are the most common fillers used in manufacturing tires. Incertain embodiments, a mixture of different fillers may beadvantageously employed.

In one or more embodiments, carbon blacks include furnace blacks,channel blacks, and lamp blacks. More specific examples of carbon blacksinclude super abrasion furnace blacks, intermediate super abrasionfurnace blacks, high abrasion furnace blacks, fast extrusion furnaceblacks, fine furnace blacks, semi-reinforcing furnace blacks, mediumprocessing channel blacks, hard processing channel blacks, conductingchannel blacks, and acetylene blacks.

In particular embodiments, the carbon blacks may have a surface area(EMSA) of at least 20 m²/g and in other embodiments at least 35 m²/g;surface area values can be determined by ASTM D-1765 using thecetyltrimethylammonium bromide (CTAB) technique. The carbon blacks maybe in a pelletized form or an unpelletized flocculent form. Thepreferred form of carbon black may depend upon the type of mixingequipment used to mix the rubber compound.

The amount of carbon black employed in the rubber compositions can be upto about 50 parts by weight per 100 parts by weight of rubber (phr),with about 5 to about 40 phr being typical.

Some commercially available silicas which may be used include Hi-Sil™215, Hi-Sil™ 233, and Hi-Sil™ 190 (PPG Industries, Inc.; Pittsburgh,Pa.). Other suppliers of commercially available silica include GraceDavison (Baltimore, Md.), Degussa Corp. (Parsippany, N.J.), RhodiaSilica Systems (Cranbury, N.J.), and J.M. Huber Corp. (Edison, N.J.).

In one or more embodiments, silicas may be characterized by theirsurface areas, which give a measure of their reinforcing character. TheBrunauer, Emmet and Teller (“BET”) method (described in J. Am. Chem.Soc., vol. 60, p. 309 et seq.) is a recognized method for determiningthe surface area. The BET surface area of silica is generally less than450 m²/g. Useful ranges of surface area include from about 32 to about400 m²/g, about 100 to about 250 m²/g, and about 150 to about 220 m²/g.

The pH's of the silicas are generally from about 5 to about 7 orslightly over 7, or in other embodiments from about 5.5 to about 6.8.

In one or more embodiments, where silica is employed as a filler (aloneor in combination with other fillers), a coupling agent and/or ashielding agent may be added to the rubber compositions during mixing inorder to enhance the interaction of silica with the elastomers. Usefulcoupling agents and shielding agents are disclosed in U.S. Pat. Nos.3,842,111, 3,873,489, 3,978,103, 3,997,581, 4,002,594, 5,580,919,5,583,245, 5,663,396, 5,674,932, 5,684,171, 5,684,172 5,696,197,6,608,145, 6,667,362, 6,579,949, 6,590,017, 6,525,118, 6,342,552, and6,683,135, which are incorporated herein by reference.

The amount of silica employed in the rubber compositions can be fromabout 1 to about 100 phr or in other embodiments from about 5 to about80 phr. The useful upper range is limited by the high viscosity impartedby silicas. When silica is used together with carbon black, the amountof silica can be decreased to as low as about 1 phr; as the amount ofsilica is decreased, lesser amounts of coupling agents and shieldingagents can be employed. Generally, the amounts of coupling agents andshielding agents range from about 4% to about 20% based on the weight ofsilica used.

A multitude of rubber curing agents (also called vulcanizing agents) maybe employed, including sulfur or peroxide-based curing systems. Curingagents are described in Kirk-Othmer, ENCYCLOPEDIA OF CHEMICALTECHNOLOGY, Vol. 20, pgs. 365-468, (3^(rd) Ed. 1982), particularlyVulcanization Agents and Auxiliary Materials, pgs. 390-402, and A. Y.Coran, Vulcanization, ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING,(2^(nd) Ed. 1989), which are incorporated herein by reference.Vulcanizing agents may be used alone or in combination.

Other ingredients that are typically employed in rubber compounding mayalso be added to the rubber compositions. These include accelerators,accelerator activators, oils, plasticizer, waxes, scorch inhibitingagents, processing aids, zinc oxide, tackifying resins, reinforcingresins, fatty acids such as stearic acid, peptizers, and antidegradantssuch as antioxidants and antiozonants. In particular embodiments, theoils that are employed include those conventionally used as extenderoils, which are described above.

All ingredients of the rubber compositions can be mixed with standardmixing equipment such as Banbury or Brabender mixers, extruders,kneaders, and two-rolled mills. In one or more embodiments, theingredients are mixed in two or more stages. In the first stage (oftenreferred to as the masterbatch mixing stage), a so-called masterbatch,which typically includes the rubber component and filler, is prepared.To prevent premature vulcanization (also known as scorch), themasterbatch may exclude vulcanizing agents. The masterbatch may be mixedat a starting temperature of from about 25° C. to about 125° C. with adischarge temperature of about 135° C. to about 180° C. Once themasterbatch is prepared, the vulcanizing agents may be introduced andmixed into the masterbatch in a final mixing stage, which is typicallyconducted at relatively low temperatures so as to reduce the chances ofpremature vulcanization. Optionally, additional mixing stages, sometimescalled remills, can be employed between the masterbatch mixing stage andthe final mixing stage. One or more remill stages are often employedwhere the rubber composition includes silica as the filler. Variousingredients including the functionalized polymers of this invention canbe added during these remills.

The mixing procedures and conditions particularly applicable tosilica-filled tire formulations are described in U.S. Pat. Nos.5,227,425, 5,719,207, and 5,717,022, as well as European Patent No.890,606, all of which are incorporated herein by reference. In oneembodiment, the initial masterbatch is prepared by including thefunctionalized polymer of this invention and silica in the substantialabsence of coupling agents and shielding agents.

The rubber compositions prepared from the functionalized polymers ofthis invention are particularly useful for forming tire components suchas treads, subtreads, sidewalls, body ply skims, bead filler, and thelike. Preferably, the functional polymers of this invention are employedin tread and sidewall formulations. In one or more embodiments, thesetread or sidewall formulations may include from about 10% to about 100%by weight, in other embodiments from about 35% to about 90% by weight,and in other embodiments from about 50% to about 80% by weight of thefunctionalized polymer based on the total weight of the rubber withinthe formulation.

Where the rubber compositions are employed in the manufacture of tires,these compositions can be processed into tire components according toordinary tire manufacturing techniques including standard rubbershaping, molding and curing techniques. Typically, vulcanization iseffected by heating the vulcanizable composition in a mold; e.g., it maybe heated to about 140° C. to about 180° C. Cured or crosslinked rubbercompositions may be referred to as vulcanizates, which generally containthree-dimensional polymeric networks that are thermoset. The otheringredients, such as fillers and processing aids, may be evenlydispersed throughout the crosslinked network. Pneumatic tires can bemade as discussed in U.S. Pat. Nos. 5,866,171, 5,876,527, 5,931,211, and5,971,046, which are incorporated herein by reference.

In order to demonstrate the practice of the present invention, thefollowing examples have been prepared and tested. The examples shouldnot, however, be viewed as limiting the scope of the invention. Theclaims will serve to define the invention.

EXAMPLES Example 1 Synthesis of Unmodified cis-1,4-Polybutadiene

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 1646 g of hexane and 2822 g of 22.5 wt % 1,3-butadienein hexane. A preformed catalyst was prepared by mixing 7.35 ml of 4.32 Mmethylaluminoxane in toluene, 1.52 g of 22.5 wt % 1,3-butadiene inhexane, 0.59 ml of 0.537 M neodymium versatate in cyclohexane, 6.67 mlof 1.0 M diisobutylaluminum hydride in hexane, and 1.27 ml of 1.0 Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. About 60 minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature and quenched with30 ml of 12 wt % 2,6-di-tert-butyl-4-methylphenol solution inisopropanol. The resulting polymer cement was coagulated with 12 litersof isopropanol containing 5 g of 2,6-di-tert-butyl-4-methylphenol andthen drum-dried. The Mooney viscosity (ML₁₊₄) of the resulting polymerwas determined to be 27.3 at 100° C. by using a Alpha TechnologiesMooney viscometer with a large rotor, a one-minute warm-up time, and afour-minute running time. As determined by gel permeation chromatography(GPC), the polymer had a number average molecular weight (M_(n)) of111,800, a weight average molecular weight (M) of 209,500, and amolecular weight distribution (M_(w)/M_(n)) of 1.87. The infraredspectroscopic analysis of the polymer indicated a cis-1,4-linkagecontent of 94.4%, a trans-1,4-linkage content of 5.1%, and a 1,2-linkagecontent of 0.5%.

The cold-flow resistance of the polymer was measured by using a Scottplasticity tester. Approximately 2.5 g of the polymer was molded, at100° C. for 20 minutes, into a cylindrical button with a diameter of 15mm and a height of 12 mm. After cooling down to room temperature, thebutton was removed from the mold and placed in a Scott plasticity testerat room temperature. A 5-kg load was applied to the specimen. After 8minutes, the residual sample gauge (i.e., sample thickness) was measuredto be 1.70 mm. Generally, the residual sample gauge can be taken as anindication of the cold-flow resistance of the polymer, with a higherresidual sample gauge indicating better cold-flow resistance.

The properties of the unmodified cis-1,4-polybutadiene are summarized inTable 1.

TABLE 1 Physical Properties of cis-1,4-Polybutadiene Example No. Example1 Example 2 Example3 Example 4 Polymer type unmodified unmodified DIPAD-DBAD- modified modified ML₁₊₄ at 100° C. 26.5 44.2 36.4 45.9 M_(n)111,800 130,700 122,200 121,000 M_(w) 209,500 260,500 222,900 224,100M_(w)/M_(n) 1.87 1.99 1.82 1.85 % cis-1,4-linkage 94.4 95.0 94.6 94.6 %trans-1,4- 5.1 4.5 4.9 4.9 linkage % 1,2-linkage 0.5 0.5 0.5 0.5Cold-flow gauge 1.70 2.14 2.24 2.55 (mm at 8 min.)

Example 2 Synthesis of Unmodified cis-1,4-Polybutadiene

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 1633 g of hexane and 2835 g of 22.4 wt % 1,3-butadienein hexane. A preformed catalyst was prepared by mixing 5.29 ml of 4.32 Mmethylaluminoxane in toluene, 1.10 g of 22.4 wt % 1,3-butadiene inhexane, 0.43 ml of 0.537 M neodymium versatate in cyclohexane, 4.80 mlof 1.0 M diisobutylaluminum hydride in hexane, and 0.91 ml of 1.0 Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. About 80 minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature and quenched with30 ml of 12 wt % 2,6-di-tert-butyl-4-methylphenol solution inisopropanol. The resulting polymer cement was coagulated with 12 litersof isopropanol containing 5 g of 2,6-di-tert-butyl-4-methylphenol andthen drum-dried. The properties of the resulting polymer are summarizedin Table 1.

Example 3 Synthesis of cis-1,4-Polybutadiene Modified with DiisopropylAzodicarboxylate (DIPAD)

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 1555 g of hexane and 2913 g of 21.8 wt % 1,3-butadienein hexane. A preformed catalyst was prepared by mixing 8.08 ml of 4.32 Mmethylaluminoxane in toluene, 1.73 g of 21.5 wt % 1,3-butadiene inhexane, 0.65 ml of 0.537 M neodymium versatate in cyclohexane, 7.33 mlof 1.0 M diisobutylaluminum hydride in hexane, and 1.40 ml of 1.0 Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. About 55 minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature.

About 432 g of the resulting unmodified polymer cement (i.e.,pseudo-living polymer cement) was transferred from the reactor to anitrogen-purged bottle, followed by addition of 5.31 ml of 0.492 Mdiisopropyl azodicarboxylate (DIPAD) in hexane. The bottle was tumbledfor 30 minutes in a water bath maintained at 65° C. The resultingpolymer cement was quenched with 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol, coagulatedwith 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting polymer are summarized in Table 1.

Example 4 Synthesis of cis-1,4-Polybutadiene Modified with DibenzylAzodicarboxylate (DBAD)

A cis-1,4-polybutadiene sample modified with dibenzyl azodicarboxylate(DBAD) was prepared by using a procedure similar to that of Example 3.The properties of the polymer are summarized in Table 1.

In FIG. 1, the cold-flow resistance of the cis-1,4-polybutadiene samplessynthesized in Examples 1-4 is plotted against the polymer Mooneyviscosity. The data indicate that, at the same polymer Mooney viscosity,the DIPAD- and DBAD-modified cis-1,4-polybutadiene samples showsignificantly higher residual sample gauge values and accordinglysignificantly better cold-flow resistance than the unmodified polymer.

Examples 5-8 Compounding Evaluation of DIPAD- and DBAD-Modifiedcis-1,4-Polybutadiene vs. Unmodified cis-1,4-Polybutadiene

The cis-1,4-polybutadiene samples produced in Examples 1-4 wereevaluated in a rubber compound filled with carbon black. Thecompositions of the vulcanizates are presented in Table 2, wherein thenumbers are expressed as parts by weight per hundred parts by weight oftotal rubber (phr).

TABLE 2 Compositions of Rubber Vulcanizates Prepared fromcis-1,4-Polybutadiene Ingredient Amount (phr) cis-1,4-Polybutadiene 80sample Polyisoprene 20 HAF Carbon black 50 Oil 10 Wax 2 Antioxidant 1Zinc oxide 2.5 Stearic acid 2 Accelerators 1.3 Sulfur 1.5 Total 170.3

The Mooney viscosity (ML₁₊₄) of the uncured rubber compound wasdetermined at 130° C. by using a Alpha Technologies Mooney viscometerwith a large rotor, a one-minute warm-up time, and a four-minute runningtime. The tensile mechanical properties (modulus, T_(b), and E_(b)) ofthe vulcanizates were measured by using the standard procedure describedin ASTM-D412. The hysteresis data (tan δ) and the Payne effect data(ΔG′) of the vulcanizates were obtained from a dynamic strain-sweepexperiment, which was conducted at 50° C. and 15 Hz with strain sweepingfrom 0.1% to 20%. ΔG′ is the difference between G′ at 0.1% strain and G′at 20% strain. The physical properties of the vulcanizates aresummarized in Table 3. In FIG. 2, the tan δ data are plotted against thecompound Mooney viscosities.

TABLE 3 Physical Properties of Rubber Vulcanizates Prepared fromcis-1,4-Polybutadiene Example No. Example 5 Example 6 Example 7 Example8 Polymer used Example 1 Example 2 Example 3 Example 4 Polymer typeunmodified unmodified DIPAD- DBAD- modified modified Compound 50.3 68.355.9 58.9 ML₁₊₄ at 130° C. 300% 10.47 10.92 11.15 11.07 modulus at 23°C. (MPa) T_(b) at 23° C. 17.9 17.4 18.3 19.1 (MPa) E_(b) at 23° C. 451425 437 456 (%) tanδ at 50° C., 0.123 0.113 0.112 0.110 3% strain ΔG′(MPa) 2.03 1.85 1.55 1.50

As can be seen in Table 3 and FIG. 2, at the same compound Mooneyviscosity, the DIPAD- and DBAD-modified cis-1,4-polybutadiene samplesgive lower tan δ than the unmodified polymer, indicating that themodification of cis-1,4-polybutadiene with DIPAD and DBAD reduceshysteresis. At the same compound Mooney viscosity, the DIPAD- andDBAD-modified cis-1,4-polybutadiene samples also give lower ΔG′ than theunmodified polymer, indicating that the Payne Effect has been reduceddue to the stronger interaction between the modified polymer and carbonblack.

What is claimed is:
 1. A method for preparing a functionalized polymer,the method comprising the steps of: (i) polymerizing monomer with alanthanide-based catalyst to form a reactive polymer, and (ii) reactingthe reactive polymer with an azodiester.
 2. The method of claim 1, wherethe azodiester is defined by the formula I:

where R¹ and R² are each independently a monovalent organic group, andeach α is independently an oxygen atom or a sulfur atom.
 3. The methodof claim 2, where each α is an oxygen atom.
 4. The method of claim 2,where one or more α atoms are sulfur atoms.
 5. The method of claim 2,where each α is a sulfur atom.
 6. The method of claim 2, where theazodiester is defined by the formula II:

where R² is a monovalent organic group, R³, R⁴, and R⁵ are eachindependently a hydrogen atom or a monovalent organic group, and each αis independently an oxygen atom or a sulfur atom.
 7. The method of claim2, where the azodiester is defined by the formula III:

where R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are each independently a hydrogen atomor a monovalent organic group, and each α is independently an oxygenatom or a sulfur atom.
 8. The method of claim 1, where the azodiester isselected from the group consisting of dihydrocarbyl azodicarboxylates,bis(trihydrocarbylsilyl)azodicarboxylates,bis(dihydrocarbylhydrosilyl)azodicarboxylates, trihydrocarbylsilylhydrocarbyl azodicarboxylates, dihydrocarbylhydrosilyl hydrocarbylazodicarboxylates, dihydrocarbyl azothiodicarboxylates,bis(trihydrocarbylsilyl)azothiodicarboxylates,bis(dihydrocarbylhydrosilyl)azothiodicarboxylates, trihydrocarbylsilylhydrocarbyl azothiodicarboxylates, and dihydrocarbylhydrosilylhydrocarbyl azothiodicarboxylates.
 9. The method of claim 1, where theazodiester is a dihydrocarbyl azodicarboxylate selected from the groupconsisting of dimethyl azodicarboxylate, diethyl azodicarboxylate,di-n-propyl azodicarboxylate, diisopropyl azodicarboxylate, di-n-butylazodicarboxylate, diisobutyl azodicarboxylate, di-t-butylazodicarboxylate, di-n-pentyl azodicarboxylate, di-n-hexylazodicarboxylate, di-n-heptyl azodicarboxylate, di-n-octylazodicarboxylate, dicyclopentyl azodicarboxylate, dicyclohexylazodicarboxylate, dibenzyl azodicarboxylate, diphenyl azodicarboxylate,di-o-tolyl azodicarboxylate, di-m-tolyl azodicarboxylate, di-p-tolylazodicarboxylate, bis(2-ethylhexyl)azodicarboxylate, methyl ethylazodicarboxylate, methyl n-propyl azodicarboxylate, ethyl n-propylazodicarboxylate, methyl isopropyl azodicarboxylate, ethyl isopropylazodicarboxylate, n-propyl isopropyl azodicarboxylate, methyl n-butylazodicarboxylate, ethyl n-butyl azodicarboxylate, n-propyl n-butylazodicarboxylate, isopropyl n-butyl azodicarboxylate, methyl isobutylazodicarboxylate, ethyl isobutyl azodicarboxylate, n-propyl isobutylazodicarboxylate, isopropyl isobutyl azodicarboxylate, n-butyl isobutylazodicarboxylate, methyl t-butyl azodicarboxylate, ethyl t-butylazodicarboxylate, n-propyl t-butyl azodicarboxylate, isopropyl t-butylazodicarboxylate, n-butyl t-butyl azodicarboxylate, isobutyl t-butylazodicarboxylate, methyl n-pentyl azodicarboxylate, ethyl n-pentylazodicarboxylate, n-propyl n-pentyl azodicarboxylate, isopropyl n-pentylazodicarboxylate, n-butyl n-pentyl azodicarboxylate, isobutyl n-pentylazodicarboxylate, t-butyl n-pentyl azodicarboxylate, methyl n-hexylazodicarboxylate, ethyl n-hexyl azodicarboxylate, n-propyl n-hexylazodicarboxylate, isopropyl n-hexyl azodicarboxylate, n-butyl n-hexylazodicarboxylate, isobutyl n-hexyl azodicarboxylate, t-butyl n-hexylazodicarboxylate, n-pentyl n-hexyl azodicarboxylate, methyl n-heptylazodicarboxylate, ethyl n-heptyl azodicarboxylate, n-propyl n-heptylazodicarboxylate, isopropyl n-heptyl azodicarboxylate, n-butyl n-heptylazodicarboxylate, isobutyl n-heptyl azodicarboxylate, t-butyl n-heptylazodicarboxylate, n-pentyl n-heptyl azodicarboxylate, n-hexyl n-heptylazodicarboxylate, methyl n-octyl azodicarboxylate, ethyl n-octylazodicarboxylate, n-propyl n-octyl azodicarboxylate, isopropyl n-octylazodicarboxylate, n-butyl n-octyl azodicarboxylate, isobutyl n-octylazodicarboxylate, t-butyl n-octyl azodicarboxylate, n-pentyl n-octylazodicarboxylate, n-hexyl n-octyl azodicarboxylate, n-heptyl n-octylazodicarboxylate, methyl cyclopentyl azodicarboxylate, ethyl cyclopentylazodicarboxylate, n-propyl cyclopentyl azodicarboxylate, isopropylcyclopentyl azodicarboxylate, n-butyl cyclopentyl azodicarboxylate,isobutyl cyclopentyl azodicarboxylate, t-butyl cyclopentylazodicarboxylate, n-pentyl cyclopentyl azodicarboxylate, n-hexylcyclopentyl azodicarboxylate, n-heptyl cyclopentyl azodicarboxylate,n-octyl cyclopentyl azodicarboxylate, methyl cyclohexylazodicarboxylate, ethyl cyclohexyl azodicarboxylate, n-propyl cyclohexylazodicarboxylate, isopropyl cyclohexyl azodicarboxylate, n-butylcyclohexyl azodicarboxylate, isobutyl cyclohexyl azodicarboxylate,t-butyl cyclohexyl azodicarboxylate, n-pentyl cyclohexylazodicarboxylate, n-hexyl cyclohexyl azodicarboxylate, n-heptylcyclohexyl azodicarboxylate, n-octyl cyclohexyl azodicarboxylate,cyclopentyl cyclohexyl azodicarboxylate, methyl benzyl azodicarboxylate,ethyl benzyl azodicarboxylate, n-propyl benzyl azodicarboxylate,isopropyl benzyl azodicarboxylate, n-butyl benzyl azodicarboxylate,isobutyl benzyl azodicarboxylate, t-butyl benzyl azodicarboxylate,n-pentyl benzyl azodicarboxylate, n-hexyl benzyl azodicarboxylate,n-heptyl benzyl azodicarboxylate, n-octyl benzyl azodicarboxylate,cyclopentyl benzyl azodicarboxylate, cyclohexyl benzyl azodicarboxylate,methyl phenyl azodicarboxylate, ethyl phenyl azodicarboxylate, n-propylphenyl azodicarboxylate, isopropyl phenyl azodicarboxylate, n-butylphenyl azodicarboxylate, isobutyl phenyl azodicarboxylate, t-butylphenyl azodicarboxylate, n-pentyl phenyl azodicarboxylate, n-hexylphenyl azodicarboxylate, n-heptyl phenyl azodicarboxylate, n-octylphenyl azodicarboxylate, cyclopentyl phenyl azodicarboxylate, cyclohexylphenyl azodicarboxylate, benzyl phenyl azodicarboxylate, methyl o-tolylazodicarboxylate, ethyl o-tolyl azodicarboxylate, n-propyl o-tolylazodicarboxylate, isopropyl o-tolyl azodicarboxylate, n-butyl o-tolylazodicarboxylate, isobutyl o-tolyl azodicarboxylate, t-butyl o-tolylazodicarboxylate, n-pentyl o-tolyl azodicarboxylate, n-hexyl o-tolylazodicarboxylate, n-heptyl o-tolyl azodicarboxylate, n-octyl o-tolylazodicarboxylate, cyclopentyl o-tolyl azodicarboxylate, cyclohexylo-tolyl azodicarboxylate, benzyl o-tolyl azodicarboxylate, phenylo-tolyl azodicarboxylate, methyl m-tolyl azodicarboxylate, ethyl m-tolylazodicarboxylate, n-propyl m-tolyl azodicarboxylate, isopropyl m-tolylazodicarboxylate, n-butyl m-tolyl azodicarboxylate, isobutyl m-tolylazodicarboxylate, t-butyl m-tolyl azodicarboxylate, n-pentyl m-tolylazodicarboxylate, n-hexyl m-tolyl azodicarboxylate, n-heptyl m-tolylazodicarboxylate, n-octyl m-tolyl azodicarboxylate, cyclopentyl m-tolylazodicarboxylate, cyclohexyl m-tolyl azodicarboxylate, benzyl m-tolylazodicarboxylate, phenyl m-tolyl azodicarboxylate, o-tolyl m-tolylazodicarboxylate, methyl p-tolyl azodicarboxylate, ethyl p-tolylazodicarboxylate, n-propyl p-tolyl azodicarboxylate, isopropyl p-tolylazodicarboxylate, n-butyl p-tolyl azodicarboxylate, isobutyl p-tolylazodicarboxylate, t-butyl p-tolyl azodicarboxylate, n-pentyl p-tolylazodicarboxylate, n-hexyl p-tolyl azodicarboxylate, n-heptyl p-tolylazodicarboxylate, n-octyl p-tolyl azodicarboxylate, cyclopentyl p-tolylazodicarboxylate, cyclohexyl p-tolyl azodicarboxylate, benzyl p-tolylazodicarboxylate, phenyl p-tolyl azodicarboxylate, o-tolyl p-tolylazodicarboxylate, m-tolyl p-tolyl azodicarboxylate, methyl 2-ethylhexylazodicarboxylate, ethyl 2-ethylhexyl azodicarboxylate, n-propyl2-ethylhexyl azodicarboxylate, isopropyl 2-ethylhexyl azodicarboxylate,n-butyl 2-ethylhexyl azodicarboxylate, isobutyl 2-ethylhexylazodicarboxylate, t-butyl 2-ethylhexyl azodicarboxylate, n-pentyl2-ethylhexyl azodicarboxylate, n-hexyl 2-ethylhexyl azodicarboxylate,n-heptyl 2-ethylhexyl azodicarboxylate, n-octyl 2-ethylhexylazodicarboxylate, cyclopentyl 2-ethylhexyl azodicarboxylate, cyclohexyl2-ethylhexyl azodicarboxylate, benzyl 2-ethylhexyl azodicarboxylate,phenyl 2-ethylhexyl azodicarboxylate, o-tolyl 2-ethylhexylazodicarboxylate, m-tolyl 2-ethylhexyl azodicarboxylate, and p-tolyl2-ethylhexyl azodicarboxylate.
 10. The method of claim 1, where theazodiester is a bis(trihydrocarbylsilyl)azodicarboxylate selected fromthe group consisting of bis(trimethylsilyl)azodicarboxylate,bis(triethylsilyl)azodicarboxylate,bis(triisopropylsilyl)azodicarboxylate,bis(tri-n-propylsilyl)azodicarboxylate,bis(triisobutylsilyl)azodicarboxylate,bis(tri-t-butylsilyl)azodicarboxylate,bis(triphenylsilyl)azodicarboxylate, trimethylsilyl triethylsilylazodicarboxylate, trimethylsilyl triisopropylsilyl azodicarboxylate,triethylsilyl triisopropylsilyl azodicarboxylate, trimethylsilyltri-n-propylsilyl azodicarboxylate, triethylsilyl tri-n-propylsilylazodicarboxylate, triisopropylsilyl tri-n-propylsilyl azodicarboxylate,trimethylsilyl triisobutylsilyl azodicarboxylate, triethylsilyltriisobutylsilyl azodicarboxylate, triisopropylsilyl triisobutylsilylazodicarboxylate, tri-n-propylsilyl triisobutylsilyl azodicarboxylate,trimethylsilyl tri-t-butylsilyl azodicarboxylate, triethylsilyltri-t-butylsilyl azodicarboxylate, triisopropylsilyl tri-t-butylsilylazodicarboxylate, tri-n-propylsilyl tri-t-butylsilyl azodicarboxylate,triisobutylsilyl tri-t-butylsilyl azodicarboxylate, trimethylsilyltriphenylsilyl azodicarboxylate, triethylsilyl triphenylsilylazodicarboxylate, triisopropylsilyl triphenylsilyl azodicarboxylate,tri-n-propylsilyl triphenylsilyl azodicarboxylate, triisobutylsilyltriphenylsilyl azodicarboxylate, and tri-t-butylsilyl triphenylsilylazodicarboxylate.
 11. The method of claim 1, where the azodiester is abis(dihydrocarbylhydrosilyl)azodicarboxylate selected from the groupconsisting of bis(dimethylhydrosilyl)azodicarboxylate,bis(diethylhydrosilyl)azodicarboxylate,bis(diisopropylhydrosilyl)azodicarboxylate,bis(di-n-propylhydrosilyl)azodicarboxylate,bis(di-t-butylhydrosilyl)azodicarboxylate,bis(diphenylhydrosilyl)azodicarboxylate, dimethylhydrosilyldiethylhydrosilyl azodicarboxylate, dimethylhydrosilyldiisopropylhydrosilyl azodicarboxylate, diethylhydrosilyldiisopropylhydrosilyl azodicarboxylate, dimethylhydrosilyldi-n-propylhydrosilyl azodicarboxylate, diethylhydrosilyldi-n-propylhydrosilyl azodicarboxylate, diisopropylhydrosilyldi-n-propylhydrosilyl azodicarboxylate, dimethylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, diethylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, diisopropylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, di-n-propylhydrosilyldi-t-butylhydrosilyl azodicarboxylate, dimethylhydrosilyldiphenylhydrosilyl azodicarboxylate, diethylhydrosilyldiphenylhydrosilyl azodicarboxylate, diisopropylhydrosilyldiphenylhydrosilyl azodicarboxylate, di-n-propylhydrosilyldiphenylhydrosilyl azodicarboxylate, and di-t-butylhydrosilyldiphenylhydrosilyl azodicarboxylate.
 12. The method of claim 1, wherethe azodiester is a trihydrocarbylsilyl hydrocarbyl azodicarboxylateselected from the group consisting of trimethylsilyl methylazodicarboxylate, triethylsilyl methyl azodicarboxylate,triisopropylsilyl methyl azodicarboxylate, tri-n-propylsilyl methylazodicarboxylate, triisobutylsilyl methyl azodicarboxylate,tri-t-butylsilyl methyl azodicarboxylate, triphenylsilyl methylazodicarboxylate, trimethylsilyl ethyl azodicarboxylate, triethylsilylethyl azodicarboxylate, triisopropylsilyl ethyl azodicarboxylate,tri-n-propylsilyl ethyl azodicarboxylate, triisobutylsilyl ethylazodicarboxylate, tri-t-butylsilyl ethyl azodicarboxylate,triphenylsilyl ethyl azodicarboxylate, trimethylsilyl n-propylazodicarboxylate, triethylsilyl n-propyl azodicarboxylate,triisopropylsilyl n-propyl azodicarboxylate, tri-n-propylsilyl n-propylazodicarboxylate, triisobutylsilyl n-propyl azodicarboxylate,tri-t-butylsilyl n-propyl azodicarboxylate, triphenylsilyl n-propylazodicarboxylate, trimethylsilyl isopropyl azodicarboxylate,triethylsilyl isopropyl azodicarboxylate, triisopropylsilyl isopropylazodicarboxylate, tri-n-propylsilyl isopropyl azodicarboxylate,triisobutylsilyl isopropyl azodicarboxylate, tri-t-butylsilyl isopropylazodicarboxylate, triphenylsilyl isopropyl azodicarboxylate,trimethylsilyl n-butyl azodicarboxylate, triethylsilyl n-butylazodicarboxylate, triisopropylsilyl n-butyl azodicarboxylate,tri-n-propylsilyl n-butyl azodicarboxylate, triisobutylsilyl n-butylazodicarboxylate, tri-t-butylsilyl n-butyl azodicarboxylate,triphenylsilyl n-butyl azodicarboxylate, trimethylsilyl isobutylazodicarboxylate, triethylsilyl isobutyl azodicarboxylate,triisopropylsilyl isobutyl azodicarboxylate, tri-n-propylsilyl isobutylazodicarboxylate, triisobutylsilyl isobutyl azodicarboxylate,tri-t-butylsilyl isobutyl azodicarboxylate, triphenylsilyl isobutylazodicarboxylate, trimethylsilyl t-butyl azodicarboxylate, triethylsilylt-butyl azodicarboxylate, triisopropylsilyl t-butyl azodicarboxylate,tri-n-propylsilyl t-butyl azodicarboxylate, triisobutylsilyl t-butylazodicarboxylate, tri-t-butylsilyl t-butyl azodicarboxylate,triphenylsilyl t-butyl azodicarboxylate, trimethylsilyl n-pentylazodicarboxylate, triethylsilyl n-pentyl azodicarboxylate,triisopropylsilyl n-pentyl azodicarboxylate, tri-n-propylsilyl n-pentylazodicarboxylate, triisobutylsilyl n-pentyl azodicarboxylate,tri-t-butylsilyl n-pentyl azodicarboxylate, triphenylsilyl n-pentylazodicarboxylate, trimethylsilyl n-hexyl azodicarboxylate, triethylsilyln-hexyl azodicarboxylate, triisopropylsilyl n-hexyl azodicarboxylate,tri-n-propylsilyl n-hexyl azodicarboxylate, triisobutylsilyl n-hexylazodicarboxylate, tri-t-butylsilyl n-hexyl azodicarboxylate,triphenylsilyl n-hexyl azodicarboxylate, trimethylsilyl n-heptylazodicarboxylate, triethylsilyl n-heptyl azodicarboxylate,triisopropylsilyl n-heptyl azodicarboxylate, tri-n-propylsilyl n-heptylazodicarboxylate, triisobutylsilyl n-heptyl azodicarboxylate,tri-t-butylsilyl n-heptyl azodicarboxylate, triphenylsilyl n-heptylazodicarboxylate, trimethylsilyl n-octyl azodicarboxylate, triethylsilyln-octyl azodicarboxylate, triisopropylsilyl n-octyl azodicarboxylate,tri-n-propylsilyl n-octyl azodicarboxylate, triisobutylsilyl n-octylazodicarboxylate, tri-t-butylsilyl n-octyl azodicarboxylate,triphenylsilyl n-octyl azodicarboxylate, trimethylsilyl cyclopentylazodicarboxylate, triethylsilyl cyclopentyl azodicarboxylate,triisopropylsilyl cyclopentyl azodicarboxylate, tri-n-propylsilylcyclopentyl azodicarboxylate, triisobutylsilyl cyclopentylazodicarboxylate, tri-t-butylsilyl cyclopentyl azodicarboxylate,triphenylsilyl cyclopentyl azodicarboxylate, trimethylsilyl cyclohexylazodicarboxylate, triethylsilyl cyclohexyl azodicarboxylate,triisopropylsilyl cyclohexyl azodicarboxylate, tri-n-propylsilylcyclohexyl azodicarboxylate, triisobutylsilyl cyclohexylazodicarboxylate, tri-t-butylsilyl cyclohexyl azodicarboxylate,triphenylsilyl cyclohexyl azodicarboxylate, trimethylsilyl benzylazodicarboxylate, triethylsilyl benzyl azodicarboxylate,triisopropylsilyl benzyl azodicarboxylate, tri-n-propylsilyl benzylazodicarboxylate, triisobutylsilyl benzyl azodicarboxylate,tri-t-butylsilyl benzyl azodicarboxylate, triphenylsilyl benzylazodicarboxylate, trimethylsilyl phenyl azodicarboxylate, triethylsilylphenyl azodicarboxylate, triisopropylsilyl phenyl azodicarboxylate,tri-n-propylsilyl phenyl azodicarboxylate, triisobutylsilyl phenylazodicarboxylate, tri-t-butylsilyl phenyl azodicarboxylate,triphenylsilyl phenyl azodicarboxylate, trimethylsilyl o-tolylazodicarboxylate, triethylsilyl o-tolyl azodicarboxylate,triisopropylsilyl o-tolyl azodicarboxylate, tri-n-propylsilyl o-tolylazodicarboxylate, triisobutylsilyl o-tolyl azodicarboxylate,tri-t-butylsilyl o-tolyl azodicarboxylate, triphenylsilyl o-tolylazodicarboxylate, trimethylsilyl m-tolyl azodicarboxylate, triethylsilylm-tolyl azodicarboxylate, triisopropylsilyl m-tolyl azodicarboxylate,tri-n-propylsilyl m-tolyl azodicarboxylate, triisobutylsilyl m-tolylazodicarboxylate, tri-t-butylsilyl m-tolyl azodicarboxylate,triphenylsilyl m-tolyl azodicarboxylate, trimethylsilyl p-tolylazodicarboxylate, triethylsilyl p-tolyl azodicarboxylate,triisopropylsilyl p-tolyl azodicarboxylate, tri-n-propylsilyl p-tolylazodicarboxylate, triisobutylsilyl p-tolyl azodicarboxylate,tri-t-butylsilyl p-tolyl azodicarboxylate, triphenylsilyl p-tolylazodicarboxylate, trimethylsilyl 2-ethylhexyl azodicarboxylate,triethylsilyl 2-ethylhexyl azodicarboxylate, triisopropylsilyl2-ethylhexyl azodicarboxylate, tri-n-propylsilyl 2-ethylhexylazodicarboxylate, triisobutylsilyl 2-ethylhexyl azodicarboxylate,tri-t-butylsilyl 2-ethylhexyl azodicarboxylate, and triphenylsilyl2-ethylhexyl azodicarboxylate.
 13. The method of claim 1, where theazodiester is a dihydrocarbylhydrosilyl hydrocarbyl azodicarboxylateselected from the group consisting of dimethylhydrosilyl methylazodicarboxylate, diethylhydrosilyl methyl azodicarboxylate,diisopropylhydrosilyl methyl azodicarboxylate, di-n-propylhydrosilylmethyl azodicarboxylate, di-t-butylhydrosilyl methyl azodicarboxylate,diphenylhydrosilyl methyl azodicarboxylate, dimethylhydrosilyl ethylazodicarboxylate, diethylhydrosilyl ethyl azodicarboxylate,diisopropylhydrosilyl ethyl azodicarboxylate, di-n-propylhydrosilylethyl azodicarboxylate, di-t-butylhydrosilyl ethyl azodicarboxylate,diphenylhydrosilyl ethyl azodicarboxylate, dimethylhydrosilyl n-propylazodicarboxylate, diethylhydrosilyl n-propyl azodicarboxylate,diisopropylhydrosilyl n-propyl azodicarboxylate, di-n-propylhydrosilyln-propyl azodicarboxylate, di-t-butylhydrosilyl n-propylazodicarboxylate, diphenylhydrosilyl n-propyl azodicarboxylate,dimethylhydrosilyl isopropyl azodicarboxylate, diethylhydrosilylisopropyl azodicarboxylate, diisopropylhydrosilyl isopropylazodicarboxylate, di-n-propylhydrosilyl isopropyl azodicarboxylate,di-t-butylhydrosilyl isopropyl azodicarboxylate, diphenylhydrosilylisopropyl azodicarboxylate, dimethylhydrosilyl n-butyl azodicarboxylate,diethylhydrosilyl n-butyl azodicarboxylate, diisopropylhydrosilyln-butyl azodicarboxylate, di-n-propylhydrosilyl n-butylazodicarboxylate, di-t-butylhydrosilyl n-butyl azodicarboxylate,diphenylhydrosilyl n-butyl azodicarboxylate, dimethylhydrosilyl isobutylazodicarboxylate, diethylhydrosilyl isobutyl azodicarboxylate,diisopropylhydrosilyl isobutyl azodicarboxylate, di-n-propylhydrosilylisobutyl azodicarboxylate, di-t-butylhydrosilyl isobutylazodicarboxylate, diphenylhydrosilyl isobutyl azodicarboxylate,dimethylhydrosilyl t-butyl azodicarboxylate, diethylhydrosilyl t-butylazodicarboxylate, diisopropylhydrosilyl t-butyl azodicarboxylate,di-n-propylhydrosilyl t-butyl azodicarboxylate, di-t-butylhydrosilylt-butyl azodicarboxylate, diphenylhydrosilyl t-butyl azodicarboxylate,dimethylhydrosilyl n-pentyl azodicarboxylate, diethylhydrosilyl n-pentylazodicarboxylate, diisopropylhydrosilyl n-pentyl azodicarboxylate,di-n-propylhydrosilyl n-pentyl azodicarboxylate, di-t-butylhydrosilyln-pentyl azodicarboxylate, diphenylhydrosilyl n-pentyl azodicarboxylate,dimethylhydrosilyl n-hexyl azodicarboxylate, diethylhydrosilyl n-hexylazodicarboxylate, diisopropylhydrosilyl n-hexyl azodicarboxylate,di-n-propylhydrosilyl n-hexyl azodicarboxylate, di-t-butylhydrosilyln-hexyl azodicarboxylate, diphenylhydrosilyl n-hexyl azodicarboxylate,dimethylhydrosilyl n-heptyl azodicarboxylate, diethylhydrosilyl n-heptylazodicarboxylate, diisopropylhydrosilyl n-heptyl azodicarboxylate,di-n-propylhydrosilyl n-heptyl azodicarboxylate, di-t-butylhydrosilyln-heptyl azodicarboxylate, diphenylhydrosilyl n-heptyl azodicarboxylate,dimethylhydrosilyl n-octyl azodicarboxylate, diethylhydrosilyl n-octylazodicarboxylate, diisopropylhydrosilyl n-octyl azodicarboxylate,di-n-propylhydrosilyl n-octyl azodicarboxylate, di-t-butylhydrosilyln-octyl azodicarboxylate, diphenylhydrosilyl n-octyl azodicarboxylate,dimethylhydrosilyl cyclopentyl azodicarboxylate, diethylhydrosilylcyclopentyl azodicarboxylate, diisopropylhydrosilyl cyclopentylazodicarboxylate, di-n-propylhydrosilyl cyclopentyl azodicarboxylate,di-t-butylhydrosilyl cyclopentyl azodicarboxylate, diphenylhydrosilylcyclopentyl azodicarboxylate, dimethylhydrosilyl cyclohexylazodicarboxylate, diethylhydrosilyl cyclohexyl azodicarboxylate,diisopropylhydrosilyl cyclohexyl azodicarboxylate, di-n-propylhydrosilylcyclohexyl azodicarboxylate, di-t-butylhydrosilyl cyclohexylazodicarboxylate, diphenylhydrosilyl cyclohexyl azodicarboxylate,dimethylhydrosilyl benzyl azodicarboxylate, diethylhydrosilyl benzylazodicarboxylate, diisopropylhydrosilyl benzyl azodicarboxylate,di-n-propylhydrosilyl benzyl azodicarboxylate, di-t-butylhydrosilylbenzyl azodicarboxylate, diphenylhydrosilyl benzyl azodicarboxylate,dimethylhydrosilyl phenyl azodicarboxylate, diethylhydrosilyl phenylazodicarboxylate, diisopropylhydrosilyl phenyl azodicarboxylate,di-n-propylhydrosilyl phenyl azodicarboxylate, di-t-butylhydrosilylphenyl azodicarboxylate, diphenylhydrosilyl phenyl azodicarboxylate,dimethylhydrosilyl o-tolyl azodicarboxylate, diethylhydrosilyl o-tolylazodicarboxylate, diisopropylhydrosilyl o-tolyl azodicarboxylate,di-n-propylhydrosilyl o-tolyl azodicarboxylate, di-t-butylhydrosilylo-tolyl azodicarboxylate, diphenylhydrosilyl o-tolyl azodicarboxylate,dimethylhydrosilyl m-tolyl azodicarboxylate, diethylhydrosilyl m-tolylazodicarboxylate, diisopropylhydrosilyl m-tolyl azodicarboxylate,di-n-propylhydrosilyl m-tolyl azodicarboxylate, di-t-butylhydrosilylm-tolyl azodicarboxylate, diphenylhydrosilyl m-tolyl azodicarboxylate,dimethylhydrosilyl p-tolyl azodicarboxylate, diethylhydrosilyl p-tolylazodicarboxylate, diisopropylhydrosilyl p-tolyl azodicarboxylate,di-n-propylhydrosilyl p-tolyl azodicarboxylate, di-t-butylhydrosilylp-tolyl azodicarboxylate, diphenylhydrosilyl p-tolyl azodicarboxylate,dimethylhydrosilyl 2-ethylhexyl azodicarboxylate, diethylhydrosilyl2-ethylhexyl azodicarboxylate, diisopropylhydrosilyl 2-ethylhexylazodicarboxylate, di-n-propylhydrosilyl 2-ethylhexyl azodicarboxylate,di-t-butylhydrosilyl 2-ethylhexyl azodicarboxylate, anddiphenylhydrosilyl 2-ethylhexyl azodicarboxylate.
 14. The method ofclaim 1, where the azodiester is a dihydrocarbyl azothiodicarboxylateselected from the group consisting of dimethyl azothiodicarboxylate,diethyl azothiodicarboxylate, di-n-propyl azothiodicarboxylate,diisopropyl azothiodicarboxylate, di-n-butyl azothiodicarboxylate,diisobutyl azothiodicarboxylate, di-t-butyl azothiodicarboxylate,di-n-pentyl azothiodicarboxylate, di-n-hexyl azothiodicarboxylate,di-n-heptyl azothiodicarboxylate, di-n-octyl azothiodicarboxylate,dicyclopentyl azothiodicarboxylate, dicyclohexyl azothiodicarboxylate,dibenzyl azothiodicarboxylate, diphenyl azothiodicarboxylate, di-o-tolylazothiodicarboxylate, di-m-tolyl azothiodicarboxylate, di-p-tolylazothiodicarboxylate, bis(2-ethylhexyl)azothiodicarboxylate, methylethyl azothiodicarboxylate, methyl n-propyl azothiodicarboxylate, ethyln-propyl azothiodicarboxylate, methyl isopropyl azothiodicarboxylate,ethyl isopropyl azothiodicarboxylate, n-propyl isopropylazothiodicarboxylate, methyl n-butyl azothiodicarboxylate, ethyl n-butylazothiodicarboxylate, n-propyl n-butyl azothiodicarboxylate, isopropyln-butyl azothiodicarboxylate, methyl isobutyl azothiodicarboxylate,ethyl isobutyl azothiodicarboxylate, n-propyl isobutylazothiodicarboxylate, isopropyl isobutyl azothiodicarboxylate, n-butylisobutyl azothiodicarboxylate, methyl t-butyl azothiodicarboxylate,ethyl t-butyl azothiodicarboxylate, n-propyl t-butylazothiodicarboxylate, isopropyl t-butyl azothiodicarboxylate, n-butylt-butyl azothiodicarboxylate, isobutyl t-butyl azothiodicarboxylate,methyl n-pentyl azothiodicarboxylate, ethyl n-pentylazothiodicarboxylate, n-propyl n-pentyl azothiodicarboxylate, isopropyln-pentyl azothiodicarboxylate, n-butyl n-pentyl azothiodicarboxylate,isobutyl n-pentyl azothiodicarboxylate, t-butyl n-pentylazothiodicarboxylate, methyl n-hexyl azothiodicarboxylate, ethyl n-hexylazothiodicarboxylate, n-propyl n-hexyl azothiodicarboxylate, isopropyln-hexyl azothiodicarboxylate, n-butyl n-hexyl azothiodicarboxylate,isobutyl n-hexyl azothiodicarboxylate, t-butyl n-hexylazothiodicarboxylate, n-pentyl n-hexyl azothiodicarboxylate, methyln-heptyl azothiodicarboxylate, ethyl n-heptyl azothiodicarboxylate,n-propyl n-heptyl azothiodicarboxylate, isopropyl n-heptylazothiodicarboxylate, n-butyl n-heptyl azothiodicarboxylate, isobutyln-heptyl azothiodicarboxylate, t-butyl n-heptyl azothiodicarboxylate,n-pentyl n-heptyl azothiodicarboxylate, n-hexyl n-heptylazothiodicarboxylate, methyl n-octyl azothiodicarboxylate, ethyl n-octylazothiodicarboxylate, n-propyl n-octyl azothiodicarboxylate, isopropyln-octyl azothiodicarboxylate, n-butyl n-octyl azothiodicarboxylate,isobutyl n-octyl azothiodicarboxylate, t-butyl n-octylazothiodicarboxylate, n-pentyl n-octyl azothiodicarboxylate, n-hexyln-octyl azothiodicarboxylate, n-heptyl n-octyl azothiodicarboxylate,methyl cyclopentyl azothiodicarboxylate, ethyl cyclopentylazothiodicarboxylate, n-propyl cyclopentyl azothiodicarboxylate,isopropyl cyclopentyl azothiodicarboxylate, n-butyl cyclopentylazothiodicarboxylate, isobutyl cyclopentyl azothiodicarboxylate, t-butylcyclopentyl azothiodicarboxylate, n-pentyl cyclopentylazothiodicarboxylate, n-hexyl cyclopentyl azothiodicarboxylate, n-heptylcyclopentyl azothiodicarboxylate, n-octyl cyclopentylazothiodicarboxylate, methyl cyclohexyl azothiodicarboxylate, ethylcyclohexyl azothiodicarboxylate, n-propyl cyclohexylazothiodicarboxylate, isopropyl cyclohexyl azothiodicarboxylate, n-butylcyclohexyl azothiodicarboxylate, isobutyl cyclohexylazothiodicarboxylate, t-butyl cyclohexyl azothiodicarboxylate, n-pentylcyclohexyl azothiodicarboxylate, n-hexyl cyclohexylazothiodicarboxylate, n-heptyl cyclohexyl azothiodicarboxylate, n-octylcyclohexyl azothiodicarboxylate, cyclopentyl cyclohexylazothiodicarboxylate, methyl benzyl azothiodicarboxylate, ethyl benzylazothiodicarboxylate, n-propyl benzyl azothiodicarboxylate, isopropylbenzyl azothiodicarboxylate, n-butyl benzyl azothiodicarboxylate,isobutyl benzyl azothiodicarboxylate, t-butyl benzylazothiodicarboxylate, n-pentyl benzyl azothiodicarboxylate, n-hexylbenzyl azothiodicarboxylate, n-heptyl benzyl azothiodicarboxylate,n-octyl benzyl azothiodicarboxylate, cyclopentyl benzylazothiodicarboxylate, cyclohexyl benzyl azothiodicarboxylate, methylphenyl azothiodicarboxylate, ethyl phenyl azothiodicarboxylate, n-propylphenyl azothiodicarboxylate, isopropyl phenyl azothiodicarboxylate,n-butyl phenyl azothiodicarboxylate, isobutyl phenylazothiodicarboxylate, t-butyl phenyl azothiodicarboxylate, n-pentylphenyl azothiodicarboxylate, n-hexyl phenyl azothiodicarboxylate,n-heptyl phenyl azothiodicarboxylate, n-octyl phenylazothiodicarboxylate, cyclopentyl phenyl azothiodicarboxylate,cyclohexyl phenyl azothiodicarboxylate, benzyl phenylazothiodicarboxylate, methyl o-tolyl azothiodicarboxylate, ethyl o-tolylazothiodicarboxylate, n-propyl o-tolyl azothiodicarboxylate, isopropylo-tolyl azothiodicarboxylate, n-butyl o-tolyl azothiodicarboxylate,isobutyl o-tolyl azothiodicarboxylate, t-butyl o-tolylazothiodicarboxylate, n-pentyl o-tolyl azothiodicarboxylate, n-hexylo-tolyl azothiodicarboxylate, n-heptyl o-tolyl azothiodicarboxylate,n-octyl o-tolyl azothiodicarboxylate, cyclopentyl o-tolylazothiodicarboxylate, cyclohexyl o-tolyl azothiodicarboxylate, benzylo-tolyl azothiodicarboxylate, phenyl o-tolyl azothiodicarboxylate,methyl m-tolyl azothiodicarboxylate, ethyl m-tolyl azothiodicarboxylate,n-propyl m-tolyl azothiodicarboxylate, isopropyl m-tolylazothiodicarboxylate, n-butyl m-tolyl azothiodicarboxylate, isobutylm-tolyl azothiodicarboxylate, t-butyl m-tolyl azothiodicarboxylate,n-pentyl m-tolyl azothiodicarboxylate, n-hexyl m-tolylazothiodicarboxylate, n-heptyl m-tolyl azothiodicarboxylate, n-octylm-tolyl azothiodicarboxylate, cyclopentyl m-tolyl azothiodicarboxylate,cyclohexyl m-tolyl azothiodicarboxylate, benzyl m-tolylazothiodicarboxylate, phenyl m-tolyl azothiodicarboxylate, o-tolylm-tolyl azothiodicarboxylate, methyl p-tolyl azothiodicarboxylate, ethylp-tolyl azothiodicarboxylate, n-propyl p-tolyl azothiodicarboxylate,isopropyl p-tolyl azothiodicarboxylate, n-butyl p-tolylazothiodicarboxylate, isobutyl p-tolyl azothiodicarboxylate, t-butylp-tolyl azothiodicarboxylate, n-pentyl p-tolyl azothiodicarboxylate,n-hexyl p-tolyl azothiodicarboxylate, n-heptyl p-tolylazothiodicarboxylate, n-octyl p-tolyl azothiodicarboxylate, cyclopentylp-tolyl azothiodicarboxylate, cyclohexyl p-tolyl azothiodicarboxylate,benzyl p-tolyl azothiodicarboxylate, phenyl p-tolylazothiodicarboxylate, o-tolyl p-tolyl azothiodicarboxylate, m-tolylp-tolyl azothiodicarboxylate, methyl 2-ethylhexyl azothiodicarboxylate,ethyl 2-ethylhexyl azothiodicarboxylate, n-propyl 2-ethylhexylazothiodicarboxylate, isopropyl 2-ethylhexyl azothiodicarboxylate,n-butyl 2-ethylhexyl azothiodicarboxylate, isobutyl 2-ethylhexylazothiodicarboxylate, t-butyl 2-ethylhexyl azothiodicarboxylate,n-pentyl 2-ethylhexyl azothiodicarboxylate, n-hexyl 2-ethylhexylazothiodicarboxylate, n-heptyl 2-ethylhexyl azothiodicarboxylate,n-octyl 2-ethylhexyl azothiodicarboxylate, cyclopentyl 2-ethylhexylazothiodicarboxylate, cyclohexyl 2-ethylhexyl azothiodicarboxylate,benzyl 2-ethylhexyl azothiodicarboxylate, phenyl 2-ethylhexylazothiodicarboxylate, o-tolyl 2-ethylhexyl azothiodicarboxylate, m-tolyl2-ethylhexyl azothiodicarboxylate, and p-tolyl 2-ethylhexylazothiodicarboxylate.
 15. The method of claim 1, where the azodiester isa bis(trihydrocarbylsilyl)azothiodicarboxylate selected from the groupconsisting of bis(trimethylsilyl)azothiodicarboxylate,bis(triethylsilyl)azothiodicarboxylate,bis(triisopropylsilyl)azothiodicarboxylate,bis(tri-n-propylsilyl)azothiodicarboxylate,bis(triisobutylsilyl)azothiodicarboxylate,bis(tri-t-butylsilyl)azothiodicarboxylate,bis(triphenylsilyl)azothiodicarboxylate, trimethylsilyl triethylsilylazothiodicarboxylate, trimethylsilyl triisopropylsilylazothiodicarboxylate, triethylsilyl triisopropylsilylazothiodicarboxylate, trimethylsilyl tri-n-propylsilylazothiodicarboxylate, triethylsilyl tri-n-propylsilylazothiodicarboxylate, triisopropylsilyl tri-n-propylsilylazothiodicarboxylate, trimethylsilyl triisobutylsilylazothiodicarboxylate, triethylsilyl triisobutylsilylazothiodicarboxylate, triisopropylsilyl triisobutylsilylazothiodicarboxylate, tri-n-propylsilyl triisobutylsilylazothiodicarboxylate, trimethylsilyl tri-t-butylsilylazothiodicarboxylate, triethylsilyl tri-t-butylsilylazothiodicarboxylate, triisopropylsilyl tri-t-butylsilylazothiodicarboxylate, tri-n-propylsilyl tri-t-butylsilylazothiodicarboxylate, triisobutylsilyl tri-t-butylsilylazothiodicarboxylate, trimethylsilyl triphenylsilylazothiodicarboxylate, triethylsilyl triphenylsilyl azothiodicarboxylate,triisopropylsilyl triphenylsilyl azothiodicarboxylate, tri-n-propylsilyltriphenylsilyl azothiodicarboxylate, triisobutylsilyl triphenylsilylazothiodicarboxylate, and tri-t-butylsilyl triphenylsilylazothiodicarboxylate.
 16. The method of claim 1, where the azodiester isa bis(dihydrocarbylhydrosilyl)azothiodicarboxylate selected from thegroup consisting of bis(dimethylhydrosilyl)azothiodicarboxylate,bis(diethylhydrosilyl)azothiodicarboxylate,bis(diisopropylhydrosilyl)azothiodicarboxylate,bis(di-n-propylhydrosilyl)azothiodicarboxylate,bis(di-t-butylhydrosilyl)azothiodicarboxylate,bis(diphenylhydrosilyl)azothiodicarboxylate, dimethylhydrosilyldiethylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldiisopropylhydrosilyl azothiodicarboxylate, diethylhydrosilyldiisopropylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldi-n-propylhydrosilyl azothiodicarboxylate, diethylhydrosilyldi-n-propylhydrosilyl azothiodicarboxylate, diisopropylhydrosilyldi-n-propylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, diethylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, diisopropylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, di-n-propylhydrosilyldi-t-butylhydrosilyl azothiodicarboxylate, dimethylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, diethylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, diisopropylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, di-n-propylhydrosilyldiphenylhydrosilyl azothiodicarboxylate, and di-t-butylhydrosilyldiphenylhydrosilyl azothiodicarboxylate.
 17. The method of claim 1,where the azodiester is a trihydrocarbylsilyl hydrocarbylazothiodicarboxylate selected from the group consisting oftrimethylsilyl methyl azothiodicarboxylate, triethylsilyl methylazothiodicarboxylate, triisopropylsilyl methyl azothiodicarboxylate,tri-n-propylsilyl methyl azothiodicarboxylate, triisobutylsilyl methylazothiodicarboxylate, tri-t-butylsilyl methyl azothiodicarboxylate,triphenylsilyl methyl azothiodicarboxylate, trimethylsilyl ethylazothiodicarboxylate, triethylsilyl ethyl azothiodicarboxylate,triisopropylsilyl ethyl azothiodicarboxylate, tri-n-propylsilyl ethylazothiodicarboxylate, triisobutylsilyl ethyl azothiodicarboxylate,tri-t-butylsilyl ethyl azothiodicarboxylate, triphenylsilyl ethylazothiodicarboxylate, trimethylsilyl n-propyl azothiodicarboxylate,triethylsilyl n-propyl azothiodicarboxylate, triisopropylsilyl n-propylazothiodicarboxylate, tri-n-propylsilyl n-propyl azothiodicarboxylate,triisobutylsilyl n-propyl azothiodicarboxylate, tri-t-butylsilyln-propyl azothiodicarboxylate, triphenylsilyl n-propylazothiodicarboxylate, trimethylsilyl isopropyl azothiodicarboxylate,triethylsilyl isopropyl azothiodicarboxylate, triisopropylsilylisopropyl azothiodicarboxylate, tri-n-propylsilyl isopropylazothiodicarboxylate, triisobutylsilyl isopropyl azothiodicarboxylate,tri-t-butylsilyl isopropyl azothiodicarboxylate, triphenylsilylisopropyl azothiodicarboxylate, trimethylsilyl n-butylazothiodicarboxylate, triethylsilyl n-butyl azothiodicarboxylate,triisopropylsilyl n-butyl azothiodicarboxylate, tri-n-propylsilyln-butyl azothiodicarboxylate, triisobutylsilyl n-butylazothiodicarboxylate, tri-t-butylsilyl n-butyl azothiodicarboxylate,triphenylsilyl n-butyl azothiodicarboxylate, trimethylsilyl isobutylazothiodicarboxylate, triethylsilyl isobutyl azothiodicarboxylate,triisopropylsilyl isobutyl azothiodicarboxylate, tri-n-propylsilylisobutyl azothiodicarboxylate, triisobutylsilyl isobutylazothiodicarboxylate, tri-t-butylsilyl isobutyl azothiodicarboxylate,triphenylsilyl isobutyl azothiodicarboxylate, trimethylsilyl t-butylazothiodicarboxylate, triethylsilyl t-butyl azothiodicarboxylate,triisopropylsilyl t-butyl azothiodicarboxylate, tri-n-propylsilylt-butyl azothiodicarboxylate, triisobutylsilyl t-butylazothiodicarboxylate, tri-t-butylsilyl t-butyl azothiodicarboxylate,triphenylsilyl t-butyl azothiodicarboxylate, trimethylsilyl n-pentylazothiodicarboxylate, triethylsilyl n-pentyl azothiodicarboxylate,triisopropylsilyl n-pentyl azothiodicarboxylate, tri-n-propylsilyln-pentyl azothiodicarboxylate, triisobutylsilyl n-pentylazothiodicarboxylate, tri-t-butylsilyl n-pentyl azothiodicarboxylate,triphenylsilyl n-pentyl azothiodicarboxylate, trimethylsilyl n-hexylazothiodicarboxylate, triethylsilyl n-hexyl azothiodicarboxylate,triisopropylsilyl n-hexyl azothiodicarboxylate, tri-n-propylsilyln-hexyl azothiodicarboxylate, triisobutylsilyl n-hexylazothiodicarboxylate, tri-t-butylsilyl n-hexyl azothiodicarboxylate,triphenylsilyl n-hexyl azothiodicarboxylate, trimethylsilyl n-heptylazothiodicarboxylate, triethylsilyl n-heptyl azothiodicarboxylate,triisopropylsilyl n-heptyl azothiodicarboxylate, tri-n-propylsilyln-heptyl azothiodicarboxylate, triisobutylsilyl n-heptylazothiodicarboxylate, tri-t-butylsilyl n-heptyl azothiodicarboxylate,triphenylsilyl n-heptyl azothiodicarboxylate, trimethylsilyl n-octylazothiodicarboxylate, triethylsilyl n-octyl azothiodicarboxylate,triisopropylsilyl n-octyl azothiodicarboxylate, tri-n-propylsilyln-octyl azothiodicarboxylate, triisobutylsilyl n-octylazothiodicarboxylate, tri-t-butylsilyl n-octyl azothiodicarboxylate,triphenylsilyl n-octyl azothiodicarboxylate, trimethylsilyl cyclopentylazothiodicarboxylate, triethylsilyl cyclopentyl azothiodicarboxylate,triisopropylsilyl cyclopentyl azothiodicarboxylate, tri-n-propylsilylcyclopentyl azothiodicarboxylate, triisobutylsilyl cyclopentylazothiodicarboxylate, tri-t-butylsilyl cyclopentyl azothiodicarboxylate,triphenylsilyl cyclopentyl azothiodicarboxylate, trimethylsilylcyclohexyl azothiodicarboxylate, triethylsilyl cyclohexylazothiodicarboxylate, triisopropylsilyl cyclohexyl azothiodicarboxylate,tri-n-propylsilyl cyclohexyl azothiodicarboxylate, triisobutylsilylcyclohexyl azothiodicarboxylate, tri-t-butylsilyl cyclohexylazothiodicarboxylate, triphenylsilyl cyclohexyl azothiodicarboxylate,trimethylsilyl benzyl azothiodicarboxylate, triethylsilyl benzylazothiodicarboxylate, triisopropylsilyl benzyl azothiodicarboxylate,tri-n-propylsilyl benzyl azothiodicarboxylate, triisobutylsilyl benzylazothiodicarboxylate, tri-t-butylsilyl benzyl azothiodicarboxylate,triphenylsilyl benzyl azothiodicarboxylate, trimethylsilyl phenylazothiodicarboxylate, triethylsilyl phenyl azothiodicarboxylate,triisopropylsilyl phenyl azothiodicarboxylate, tri-n-propylsilyl phenylazothiodicarboxylate, triisobutylsilyl phenyl azothiodicarboxylate,tri-t-butylsilyl phenyl azothiodicarboxylate, triphenylsilyl phenylazothiodicarboxylate, trimethylsilyl o-tolyl azothiodicarboxylate,triethylsilyl o-tolyl azothiodicarboxylate, triisopropylsilyl o-tolylazothiodicarboxylate, tri-n-propylsilyl o-tolyl azothiodicarboxylate,triisobutylsilyl o-tolyl azothiodicarboxylate, tri-t-butylsilyl o-tolylazothiodicarboxylate, triphenylsilyl o-tolyl azothiodicarboxylate,trimethylsilyl m-tolyl azothiodicarboxylate, triethylsilyl m-tolylazothiodicarboxylate, triisopropylsilyl m-tolyl azothiodicarboxylate,tri-n-propylsilyl m-tolyl azothiodicarboxylate, triisobutylsilyl m-tolylazothiodicarboxylate, tri-t-butylsilyl m-tolyl azothiodicarboxylate,triphenylsilyl m-tolyl azothiodicarboxylate, trimethylsilyl p-tolylazothiodicarboxylate, triethylsilyl p-tolyl azothiodicarboxylate,triisopropylsilyl p-tolyl azothiodicarboxylate, tri-n-propylsilylp-tolyl azothiodicarboxylate, triisobutylsilyl p-tolylazothiodicarboxylate, tri-t-butylsilyl p-tolyl azothiodicarboxylate,triphenylsilyl p-tolyl azothiodicarboxylate, trimethylsilyl 2-ethylhexylazothiodicarboxylate, triethylsilyl 2-ethylhexyl azothiodicarboxylate,triisopropylsilyl 2-ethylhexyl azothiodicarboxylate, tri-n-propylsilyl2-ethylhexyl azothiodicarboxylate, triisobutylsilyl 2-ethylhexylazothiodicarboxylate, tri-t-butylsilyl 2-ethylhexylazothiodicarboxylate, and triphenylsilyl 2-ethylhexylazothiodicarboxylate.
 18. The method of claim 1, where the azodiester isa dihydrocarbylhydrosilyl hydrocarbyl azothiodicarboxylate selected fromthe group consisting of dimethylhydrosilyl methyl azothiodicarboxylate,diethylhydrosilyl methyl azothiodicarboxylate, diisopropylhydrosilylmethyl azothiodicarboxylate, di-n-propylhydrosilyl methylazothiodicarboxylate, di-t-butylhydrosilyl methyl azothiodicarboxylate,diphenylhydrosilyl methyl azothiodicarboxylate, dimethylhydrosilyl ethylazothiodicarboxylate, diethylhydrosilyl ethyl azothiodicarboxylate,diisopropylhydrosilyl ethyl azothiodicarboxylate, di-n-propylhydrosilylethyl azothiodicarboxylate, di-t-butylhydrosilyl ethylazothiodicarboxylate, diphenylhydrosilyl ethyl azothiodicarboxylate,dimethylhydrosilyl n-propyl azothiodicarboxylate, diethylhydrosilyln-propyl azothiodicarboxylate, diisopropylhydrosilyl n-propylazothiodicarboxylate, di-n-propylhydrosilyl n-propylazothiodicarboxylate, di-t-butylhydrosilyl n-propylazothiodicarboxylate, diphenylhydrosilyl n-propyl azothiodicarboxylate,dimethylhydrosilyl isopropyl azothiodicarboxylate, diethylhydrosilylisopropyl azothiodicarboxylate, diisopropylhydrosilyl isopropylazothiodicarboxylate, di-n-propylhydrosilyl isopropylazothiodicarboxylate, di-t-butylhydrosilyl isopropylazothiodicarboxylate, diphenylhydrosilyl isopropyl azothiodicarboxylate,dimethylhydrosilyl n-butyl azothiodicarboxylate, diethylhydrosilyln-butyl azothiodicarboxylate, diisopropylhydrosilyl n-butylazothiodicarboxylate, di-n-propylhydrosilyl n-butylazothiodicarboxylate, di-t-butylhydrosilyl n-butyl azothiodicarboxylate,diphenylhydrosilyl n-butyl azothiodicarboxylate, dimethylhydrosilylisobutyl azothiodicarboxylate, diethylhydrosilyl isobutylazothiodicarboxylate, diisopropylhydrosilyl isobutylazothiodicarboxylate, di-n-propylhydrosilyl isobutylazothiodicarboxylate, di-t-butylhydrosilyl isobutylazothiodicarboxylate, diphenylhydrosilyl isobutyl azothiodicarboxylate,dimethylhydrosilyl t-butyl azothiodicarboxylate, diethylhydrosilylt-butyl azothiodicarboxylate, diisopropylhydrosilyl t-butylazothiodicarboxylate, di-n-propylhydrosilyl t-butylazothiodicarboxylate, di-t-butylhydrosilyl t-butyl azothiodicarboxylate,diphenylhydrosilyl t-butyl azothiodicarboxylate, dimethylhydrosilyln-pentyl azothiodicarboxylate, diethylhydrosilyl n-pentylazothiodicarboxylate, diisopropylhydrosilyl n-pentylazothiodicarboxylate, di-n-propylhydrosilyl n-pentylazothiodicarboxylate, di-t-butylhydrosilyl n-pentylazothiodicarboxylate, diphenylhydrosilyl n-pentyl azothiodicarboxylate,dimethylhydrosilyl n-hexyl azothiodicarboxylate, diethylhydrosilyln-hexyl azothiodicarboxylate, diisopropylhydrosilyl n-hexylazothiodicarboxylate, di-n-propylhydrosilyl n-hexylazothiodicarboxylate, di-t-butylhydrosilyl n-hexyl azothiodicarboxylate,diphenylhydrosilyl n-hexyl azothiodicarboxylate, dimethylhydrosilyln-heptyl azothiodicarboxylate, diethylhydrosilyl n-heptylazothiodicarboxylate, diisopropylhydrosilyl n-heptylazothiodicarboxylate, di-n-propylhydrosilyl n-heptylazothiodicarboxylate, di-t-butylhydrosilyl n-heptylazothiodicarboxylate, diphenylhydrosilyl n-heptyl azothiodicarboxylate,dimethylhydrosilyl n-octyl azothiodicarboxylate, diethylhydrosilyln-octyl azothiodicarboxylate, diisopropylhydrosilyl n-octylazothiodicarboxylate, di-n-propylhydrosilyl n-octylazothiodicarboxylate, di-t-butylhydrosilyl n-octyl azothiodicarboxylate,diphenylhydrosilyl n-octyl azothiodicarboxylate, dimethylhydrosilylcyclopentyl azothiodicarboxylate, diethylhydrosilyl cyclopentylazothiodicarboxylate, diisopropylhydrosilyl cyclopentylazothiodicarboxylate, di-n-propylhydrosilyl cyclopentylazothiodicarboxylate, di-t-butylhydrosilyl cyclopentylazothiodicarboxylate, diphenylhydrosilyl cyclopentylazothiodicarboxylate, dimethylhydrosilyl cyclohexylazothiodicarboxylate, diethylhydrosilyl cyclohexyl azothiodicarboxylate,diisopropylhydrosilyl cyclohexyl azothiodicarboxylate,di-n-propylhydrosilyl cyclohexyl azothiodicarboxylate,di-t-butylhydrosilyl cyclohexyl azothiodicarboxylate, diphenylhydrosilylcyclohexyl azothiodicarboxylate, dimethylhydrosilyl benzylazothiodicarboxylate, diethylhydrosilyl benzyl azothiodicarboxylate,diisopropylhydrosilyl benzyl azothiodicarboxylate, di-n-propylhydrosilylbenzyl azothiodicarboxylate, di-t-butylhydrosilyl benzylazothiodicarboxylate, diphenylhydrosilyl benzyl azothiodicarboxylate,dimethylhydrosilyl phenyl azothiodicarboxylate, diethylhydrosilyl phenylazothiodicarboxylate, diisopropylhydrosilyl phenyl azothiodicarboxylate,di-n-propylhydrosilyl phenyl azothiodicarboxylate, di-t-butylhydrosilylphenyl azothiodicarboxylate, diphenylhydrosilyl phenylazothiodicarboxylate, dimethylhydrosilyl o-tolyl azothiodicarboxylate,diethylhydrosilyl o-tolyl azothiodicarboxylate, diisopropylhydrosilylo-tolyl azothiodicarboxylate, di-n-propylhydrosilyl o-tolylazothiodicarboxylate, di-t-butylhydrosilyl o-tolyl azothiodicarboxylate,diphenylhydrosilyl o-tolyl azothiodicarboxylate, dimethylhydrosilylm-tolyl azothiodicarboxylate, diethylhydrosilyl m-tolylazothiodicarboxylate, diisopropylhydrosilyl m-tolylazothiodicarboxylate, di-n-propylhydrosilyl m-tolylazothiodicarboxylate, di-t-butylhydrosilyl m-tolyl azothiodicarboxylate,diphenylhydrosilyl m-tolyl azothiodicarboxylate, dimethylhydrosilylp-tolyl azothiodicarboxylate, diethylhydrosilyl p-tolylazothiodicarboxylate, diisopropylhydrosilyl p-tolylazothiodicarboxylate, di-n-propylhydrosilyl p-tolylazothiodicarboxylate, di-t-butylhydrosilyl p-tolyl azothiodicarboxylate,diphenylhydrosilyl p-tolyl azothiodicarboxylate, dimethylhydrosilyl2-ethylhexyl azothiodicarboxylate, diethylhydrosilyl 2-ethylhexylazothiodicarboxylate, diisopropylhydrosilyl 2-ethylhexylazothiodicarboxylate, di-n-propylhydrosilyl 2-ethylhexylazothiodicarboxylate, di-t-butylhydrosilyl 2-ethylhexylazothiodicarboxylate, and diphenylhydrosilyl 2-ethylhexylazothiodicarboxylate.
 19. The method of claim 1, where the monomerincludes conjugated diene monomer.
 20. The method of claim 1, where thelanthanide-based catalyst includes (a) a lanthanide-containing compound,(b) an alkylating agent, and (c) a halogen source.
 21. The method ofclaim 20, where the alkylating agent includes an aluminoxane and anorganoaluminum compound represented by the formula AlR_(n)X_(3−n), whereeach R, which may be the same or different, is a monovalent organicgroup that is attached to the aluminum atom via a carbon atom, whereeach X, which may be the same or different, is a hydrogen atom, ahalogen atom, a carboxylate group, an alkoxide group, or an aryloxidegroup, and where n is an integer of 1 to
 3. 22. The method of claim 1,where said step of polymerizing monomer takes place within apolymerization mixture including less than 20% by weight of organicsolvent.
 23. A method for preparing a functionalized polymer, the methodcomprising the steps of: (i) polymerizing, with a lanthanide-basedcatalyst, conjugated diene monomer, and optionally monomercopolymerizable therewith, to form a polymer having a reactive chainend; and (ii) reacting the reactive chain end of the polymer with anazodiester.
 24. The method of claim 23, further comprising the step ofprotonating the polymer after said step of reacting.
 25. Afunctionalized polymer prepared by the steps of: (i) polymerizing, witha lanthanide-based catalyst, conjugated diene monomer, and optionallymonomer copolymerizable therewith, to form a polymer having a reactivechain end; and (ii) reacting the reactive chain end of the polymer withan azodiester.
 26. A tire component prepared by employing thefunctionalized polymer of claim
 25. 27. A vulcanizable compositioncomprising: the functionalized polymer of claim 25, a filler, and acurative.